@article{MTMT:34641136, title = {A Three-Dimensional Fully-Coupled Fluid-Structure Model for Tsunami Loading on Coastal Bridges}, url = {https://m2.mtmt.hu/api/publication/34641136}, author = {Baragamage, Dilshan S. P. Amarasinghe and Wu, Weiming}, doi = {10.3390/w16010189}, journal-iso = {WATER-SUI}, journal = {WATER}, volume = {16}, unique-id = {34641136}, keywords = {Immersed boundary method; fluid-structure interactions; Three-dimensional model; Fully-coupled; tsunami loading; cut-cell method}, year = {2024}, eissn = {2073-4441} } @article{MTMT:34641137, title = {Hydrodynamic analysis and optimization of a floating wave energy converter with moonpool using OpenFOAM®}, url = {https://m2.mtmt.hu/api/publication/34641137}, author = {Khan, Muhammad Ahsan and Barajas, Gabriel and Gaeta, Maria Gabriella and Lara, Javier Lopez and Archetti, Renata}, doi = {10.1016/j.apor.2023.103847}, journal-iso = {APPL OCEAN RES}, journal = {APPLIED OCEAN RESEARCH}, volume = {142}, unique-id = {34641137}, issn = {0141-1187}, keywords = {Floating body; CFD; OpenFOAM; Numerical wave tank; WECs; moonpool; Wave -structure interaction}, year = {2024}, eissn = {1879-1549} } @article{MTMT:34321749, title = {SWELL: An open-access experimental dataset for arrays of wave energy conversion systems}, url = {https://m2.mtmt.hu/api/publication/34321749}, author = {Faedo, Nicolas and Pena-Sanchez, Yerai and Pasta, Edoardo and Papini, Guglielmo and Mosquera, Facundo D. and Ferri, Francesco}, doi = {10.1016/j.renene.2023.05.069}, journal-iso = {RENEW ENERGY}, journal = {RENEWABLE ENERGY}, volume = {212}, unique-id = {34321749}, issn = {0960-1481}, abstract = {Achieving large-scale commercial exploitation of ocean wave energy inherently encompasses the design and deployment of arrays of wave energy converters (WECs), in an effort to reduce the associated levelised cost of energy. In this context, understanding the interactions between devices in a controlled WEC array is hence essential to achieve optimal layout configurations, as well as to provide guidance on the area required for array installation, reliability, life-time, and overall cost of the farm. Successful achievement of these vital objectives for the wave energy industry has been constantly aided by the use of appropriate numerical models. Regardless of the specific modelling approach adopted, model reliability is always a major concern: Numerical models need to able be to represent reality to be useful in supporting the different stages of development, hence providing significant results for decision making. To test reliability of a model, experimental results are an invaluable asset for validation.Recognising the striking absence of real-world data concerning arrays of WEC systems, and its inherent value for model validation and data-based modelling purposes, we present, in this paper, an experimental campaign fully conducted with the sole objective of generating and providing an open-access dataset on WEC farms: SWELL (Standardised Wave Energy converter array Learning Library). The generated dataset, included alongside this manuscript, comprises an approximate total of similar to 3000 variables and more than similar to 108 datapoints, for up to 5 devices in 9 diverse WEC array layouts with different levels of interaction, and 19 carefully selected operating conditions. Four different categories of tests are considered, providing measures of key variables required for model validation and data-based modelling tasks. As such, SWELL provides a crucial resource to achieve confidence in numerical modelling, helping towards creating reliable tools for decision making in the WEC field, hence effectively supporting the pathway towards effective commercialisation of ocean wave energy.}, keywords = {Wave energy; ARRAY; model validation; farm; wave energy converters; Data-based modelling}, year = {2023}, eissn = {1879-0682}, pages = {699-716}, orcid-numbers = {Pasta, Edoardo/0000-0001-9525-6284; Papini, Guglielmo/0000-0002-6302-0522} } @article{MTMT:33567554, title = {Representative linearised models for a wave energy converter using various levels of force excitation}, url = {https://m2.mtmt.hu/api/publication/33567554}, author = {Farajvand, Mahdiyeh and García-Violini, Demián and Ringwood, John V}, doi = {10.1016/j.oceaneng.2023.113635}, journal-iso = {OCEAN ENG}, journal = {OCEAN ENGINEERING}, volume = {270}, unique-id = {33567554}, issn = {0029-8018}, year = {2023}, eissn = {1873-5258} } @article{MTMT:33942588, title = {Hydrodynamics of an idealized reef-lagoon-channel coastal system: A three-dimensional CFD simulation}, url = {https://m2.mtmt.hu/api/publication/33942588}, author = {Huang, Shijie and Huang, Zhenhua}, doi = {10.1016/j.coastaleng.2023.104314}, journal-iso = {COAST ENG}, journal = {COASTAL ENGINEERING}, volume = {183}, unique-id = {33942588}, issn = {0378-3839}, abstract = {A three-dimensional (3D) numerical model that solves the Reynolds-Averaged Navier-Stokes (RANS) equations coupled with k - ! turbulence closure and VOF method is developed with the open source CFD tool OpenFOAM to simulate the hydrodynamics in an idealized reef-lagoon-channel coastal system. Comparison with experimental measurements shows satisfactory agreements in terms of the wave transformation, wave -induced setup and the mean current. The validated simulation result is further analyzed to investigate the detailed wave transformation, mass and momentum transport processes in the reef-lagoon-channel system, where both the differential and integral form of the depth-integrated time-averaged momentum equations are applied. The mass balance shows that the cross-shore flow on the reef flat is almost uniform on cross-shore transects away from the channel, while the lagoonal flow gradually increases in strength as it approaches the channel. The cross-shore momentum balance shows that the excess momentum flux and hydrostatic pressure forces dominate in the shoaling and breaker zones as expected, while the bottom friction force plays a more important role in the breaker zone than previous studies assumed. On the reef flat where the wave forces become weak, the integral form of the momentum balance shows advantages over the differential form due to its higher accuracy, which enables us to identify that the bottom friction and hydrostatic pressure forces dominate the momentum balance on the reef flat. Finally, the reliability of the differential and integral form of momentum equations and the effect of a depth non-uniform current on the excess momentum flux are discussed.}, keywords = {coral reef; OpenFOAM; Littoral cell; Wave transformation; Wave setup; Rip current}, year = {2023}, eissn = {1872-7379} } @article{MTMT:33942590, title = {On wave-current interaction in deep and finite water depths}, url = {https://m2.mtmt.hu/api/publication/33942590}, author = {Kumar, Arun and Hayatdavoodi, Masoud}, doi = {10.1007/s40722-023-00278-x}, journal-iso = {J. Ocean Eng. Mar. Energy}, journal = {Journal of Ocean Engineering and Marine Energy}, unique-id = {33942590}, issn = {2198-6444}, abstract = {Interaction of linear and nonlinear, long-crested waves with currents in deep and finite water depths is studied by use of the computational fluid dynamics approach. Various wave conditions are considered by systematically changing the wave height and the wavelength. Several current profiles are studied as polynomial functions of water depth following the profiles and magnitudes of the available ocean current data. Both following and opposing currents are considered, and in total, 26 wave-current configurations are investigated. The two-dimensional study is carried out computationally by solving the Navier-Stokes equations for a laminar flow. The governing equations are solved by use of the finite volume approach in an open-source computational fluid dynamics package, namely OpenFOAM. Modifications are made to an existing wave-making toolbox, waves2Foam, to generate combined nonlinear waves and currents in deep and finite waters. Results of the numerical wave-current tank are compared with the existing laboratory measurements and overall very good agreement is observed. Discussion is provided on the effect of these currents on the change of the wave field, including quantitative change of the surface elevation, wave profile, pressure distribution, and fluid particle velocity of waves. Overall, it is observed that opposing current has a remarkable impact on the wave field, and the particle velocity and wave height are affected the most from the presence of the current.}, keywords = {Wave-current interaction; Shearing current; Opposing current; Following current; Wave deformation}, year = {2023}, orcid-numbers = {Hayatdavoodi, Masoud/0000-0003-3554-3438} } @article{MTMT:33932220, title = {Hydrodynamic performance analysis of a new hybrid wave energy converter system using OpenFOAM}, url = {https://m2.mtmt.hu/api/publication/33932220}, author = {Masoomi, Mobin and Sarlak, Hamid and Rezanejad, Kourosh}, doi = {10.1016/j.energy.2023.126807}, journal-iso = {ENERGY}, journal = {ENERGY}, volume = {269}, unique-id = {33932220}, issn = {0360-5442}, abstract = {In this research study, a newly proposed hybrid device of Wave Energy Converters (WEC) is investigated by considering computational fluid dynamic (CFD)-based numerical wave tanks (NWTs). The open-source CFD code solver, OpenFOAM (Open Field Operation and Manipulation) is implemented, which is numerically solved the Reynolds-averaged Navier-Stokes (RANS) equations to simulate the two-phase flow. The hybrid system consists of an Oscillating Water Column (OWC) and a point absorber (Wavestar) device installed in a shared platform. The main goal is to recognize how wave diffractions caused by the adjacent floating body could affect the rate of power absorption by the Fixed-OWC. This aim is followed by a 2D numerical analysis of three different instal-lation configurations, variable intervals between the Wavestars' buoy and the Fixed-OWCs' front wall, in four different wavelengths with and without Power Take-Off (PTO). Finally, the efficiency characteristics of the in-tegrated system such as free surface velocity and air pressure within the chamber, besides floating body motions are investigated and compared for the hybrid system. Although the overall assessment for 28 different case studies reveals an efficiency reduction in some cases, the superiority of this hybrid plan is recording several incremental efficiency rates.}, keywords = {Oscillating water column; Wavestar; Hybrid wave energy converter; OverInterDyMFoam}, year = {2023}, eissn = {1873-6785} } @article{MTMT:33588813, title = {Predicting hydrodynamic forces on heave plates using a data-driven modelling architecture}, url = {https://m2.mtmt.hu/api/publication/33588813}, author = {Mishra, Virag and Crawford, Curran and Buckham, Bradley}, doi = {10.1016/j.jfluidstructs.2022.103812}, journal-iso = {J FLUID STRUCT}, journal = {JOURNAL OF FLUIDS AND STRUCTURES}, volume = {116}, unique-id = {33588813}, issn = {0889-9746}, year = {2023}, eissn = {1095-8622}, orcid-numbers = {Crawford, Curran/0000-0001-6047-728X} } @article{MTMT:34331823, title = {Determination of Formulae for the Hydrodynamic Performance of a Fixed Box-Type Free Surface Breakwater in the Intermediate Water}, url = {https://m2.mtmt.hu/api/publication/34331823}, author = {Niu, Guoxu and Chen, Yaoyong and Lv, Jiao and Zhang, Jing and Fan, Ning}, doi = {10.3390/jmse11091812}, journal-iso = {J MAR SCI ENG}, journal = {JOURNAL OF MARINE SCIENCE AND ENGINEERING}, volume = {11}, unique-id = {34331823}, abstract = {A two-dimensional viscous numerical wave tank coded mass source function in a computational fluid dynamics (CFD) software Flow-3D 11.2 is built and validated. The effect of the core influencing factors (draft, breakwater width, wave period, and wave height) on the hydrodynamic performance of a fixed box-type free surface breakwater (abbreviated to F-BW in the following texts) are highlighted in the intermediate waters. The results show that four influence factors, except wave period, impede wave transmission; the draft and breakwater width boost wave reflection, and the wave period and wave height are opposite; the draft impedes wave energy dissipation, and the wave height is opposite; the draft and wave height boost the horizontal extreme wave force; four influence factors, except the draft, boost the vertical extreme wave force. Finally, new formulas are provided to determine the transmission, reflection, and dissipation coefficients and extreme wave forces of the F-BW by applying multiple linear regression. The new formulas are verified by comparing with existing literature observation datasets. The results show that it is in good agreement with previous datasets.}, keywords = {Numerical wave tank; Breakwater; regular wave; wave force; prediction formulae}, year = {2023}, eissn = {2077-1312}, orcid-numbers = {Fan, Ning/0000-0002-1654-9423} } @article{MTMT:34331824, title = {High-fidelity modelling of lift-based wave energy converters in a numerical wave tank}, url = {https://m2.mtmt.hu/api/publication/34331824}, author = {Olbert, Gerrit and Abdel-Maksoud, Moustafa}, doi = {10.1016/j.apenergy.2023.121460}, journal-iso = {APPL ENERG}, journal = {APPLIED ENERGY}, volume = {347}, unique-id = {34331824}, issn = {0306-2619}, abstract = {This work presents the development of a numerical model for the investigation of lift-based wave energy converter (lift-WEC) hydrodynamics. The developed model, based on the RANS equation, is validated regarding its ability to replicate foil-flow interaction in various conditions based on experimental references from literature. Limitations of the numerical model are discussed, such as the overprediction of stall angles at low Reynolds numbers and the possibility of artificial rotor ventilation near the free surface. Within the range of relevant operating conditions for a lift-WEC, the model is found to replicate experimental results with good accuracy. Subsequently, a particularity of the cyclorotor WEC concept is investigated: Load measurements in calm water showed positive tangential forces, apparently indicating the generation of thrust in the absence of external energy sources. Numerical simulations reveal that this is the result of a significant azimuthal shift of the hydrodynamic load centre for non-zero pitch and that the consideration of foil pitch moments is required in order to obtain accurate shaft torque predictions. The hydrodynamic coefficients of the cyclorotor foils are compared with coefficients obtained for symmetrical foils in straight flight. It is shown that the assumption of similarity, which is often applied when modelling these devices in semi-analytical tools, is only valid for small angles of attack.}, keywords = {Numerical modelling; hydrodynamics; Wave energy; CFD; Cyclorotor; Hydrofoils}, year = {2023}, eissn = {1872-9118} } @article{MTMT:33600379, title = {A review of computational methods for studying oscillating water columns–the Navier-Stokes based equation approach}, url = {https://m2.mtmt.hu/api/publication/33600379}, author = {Opoku, F and Uddin, MN and Atkinson, M}, doi = {10.1016/j.rser.2022.113124}, journal-iso = {RENEW SUST ENERG REV}, journal = {RENEWABLE & SUSTAINABLE ENERGY REVIEWS}, volume = {174}, unique-id = {33600379}, issn = {1364-0321}, year = {2023}, eissn = {1879-0690}, pages = {113124} } @article{MTMT:34331826, title = {A numerical experiment on a new piston-type wavemaker: Shallow water approximation}, url = {https://m2.mtmt.hu/api/publication/34331826}, author = {Park, Jinsoo and Cho, Daeseung and Jang, Taeksoo}, doi = {10.1016/j.ijnaoe.2023.100535}, journal-iso = {INT J NAV ARCH OCEAN}, journal = {International Journal of Naval Architecture and Ocean Engineering}, volume = {15}, unique-id = {34331826}, issn = {2092-6782}, abstract = {In this paper, we present a numerical experiment on a new piston-type wavemaker using a recently proposed piston-type wavemaker theory. The theory was primarily derived from the classical Boussinesq equation, based on the Pseudo-parameter Iteration Method (PIM). We first use the new theory to observe low amplitude propagating solitary waves and cnoidal waves, whereby we see the workability and validity of the theory. We further succeed in obtaining the graph of a mean power characteristic, in the range of 0.4 < kh < 1.0, of the new piston-type wavemaker from the new theory.& COPY; 2023 Society of Naval Architects of Korea. Production and hosting by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).}, keywords = {Mean power; Piston-type wavemaker theory; Pseudo -parameter iteration method; Classical boussinesq equation}, year = {2023}, eissn = {2092-6790} } @article{MTMT:34331825, title = {Numerical modeling of water waves with the highly efficient and accurate Lagrangian-Eulerian stabilized collocation method (LESCM)}, url = {https://m2.mtmt.hu/api/publication/34331825}, author = {Qian, Zhihao and Wang, Lihua and Zhang, Chuanzeng and Liu, Qihang and Chen, Qiang and Lu, Xilin}, doi = {10.1016/j.apor.2023.103672}, journal-iso = {APPL OCEAN RES}, journal = {APPLIED OCEAN RESEARCH}, volume = {138}, unique-id = {34331825}, issn = {0141-1187}, abstract = {A novel numerical wave tank (NWT) based on the Lagrangian-Eulerian stabilized collocation method (LESCM) is constructed for modeling water waves, in which the piston-type wavemaker is employed for wave generation, and the relaxation zone technique is used for wave absorption. The LESCM is an evolution version of the particlein-cell method. In its discretization scheme, a background mesh covering the entire tank is introduced for solving the incompressible Navier-Stokes equations by the stabilized collocation method (SCM), and the water inside is discretized by Lagrangian particles which shuttle within the Eulerian mesh. Then, the Eulerian mesh communicates with Lagrangian particles through high-order consistent reproducing kernel (RK) interpolation. Besides, the mesh is initialized at the beginning of each time step, which can avoid the reconstruction of shape functions and dramatically reduce computational efforts. Furthermore, the numerical solution of the SCM is locally and globally conserved since the SCM is a subdomain method just like the finite volume method. Moreover, the information transfer between nodes and particles satisfies the conservation property, which makes the novel NWT a fully conservative model. Several numerical examples demonstrate that the proposed NWT is highly efficient, accurate and stable, and hence can be applied to the research of coastal and offshore engineering.}, keywords = {method; reproducing kernel; INCOMPRESSIBLE FLUID; Numerical wave tank; Local conservation; High efficiency and accuracy; Lagrangian-Eulerian stabilized collocation}, year = {2023}, eissn = {1879-1549} } @article{MTMT:34641138, title = {Comparing the Utility of Coupled Aero-Hydrodynamic Analysis Using a CFD Solver versus a Potential Flow Solver for Floating Offshore Wind Turbines}, url = {https://m2.mtmt.hu/api/publication/34641138}, author = {Siddiqui, Mohd Atif and Hanssen, Finn-Christian Wickmann and Greco, Marilena and Anda, Eirik}, doi = {10.3390/en16237833}, journal-iso = {ENERGIES}, journal = {ENERGIES}, volume = {16}, unique-id = {34641138}, issn = {1996-1073}, keywords = {Renewable energy; CFD; Floating offshore wind turbine; potential-flow methods}, year = {2023}, eissn = {1996-1073}, orcid-numbers = {Hanssen, Finn-Christian Wickmann/0000-0002-6001-4645} } @article{MTMT:33942589, title = {Comparative Study of Potential Flow and CFD in the Assessment of Seakeeping and Added Resistance of Ships}, url = {https://m2.mtmt.hu/api/publication/33942589}, author = {Sulovsky, Ivan and de Hauteclocque, Guillaume and Greco, Marilena and Prpic-Orsic, Jasna}, doi = {10.3390/jmse11030641}, journal-iso = {J MAR SCI ENG}, journal = {JOURNAL OF MARINE SCIENCE AND ENGINEERING}, volume = {11}, unique-id = {33942589}, abstract = {The need for maritime freight transport of various goods has never been greater. Consequently, ships are designed with ever-increasing dimensions, with the emphasis, of course, on length. One of the many challenges in the design of large ships is the prediction of their behavior in waves, i.e., motions, and consequently, added resistance. In this paper, a comparative study of two numerical tools for estimating ship motions and added resistance is presented. The first tool is the well-established DNV's commercial seakeeping code Wasim, a weakly nonlinear potential flow (PF) solver based on a Rankine panel method. The other is the increasingly recognized open-source Computational Fluid Dynamic (CFD) toolkit OpenFOAM(R), a viscous flow solver with a turbulence model; it is based on the finite volume method (FVM) combined with a volume-of-fluid (VOF) technique for sea-surface evolution. The study is carried out for two ship seakeeping cases in head-sea regular waves, respectively, without and with ship forward speed. The first case refers to a 6750 TEU containership scale model developed at the LHEEA laboratory in Nantes for a benchmark study, providing experimental data for all test cases. Pitch and heave response is calculated and compared with the experimental values. The second case refers to a KRISO container ship, an extensively researched hull model in ship hydrodynamics. In addition to the pitch and heave, added resistance is also calculated and compared with the experimental values. Hence, it provides a comprehensive basis for a comparative analysis between the selected solvers. The results are systematically analyzed and discussed in detail. For both cases, deterioration of the PF solution with increasing wave steepness is observed, thus suggesting limitations in the modeled nonlinear effects as a possible reason. The accuracy of the CFD solver greatly depends on the spatial discretization characteristics, thus suggesting the need for grid independence studies, as such tools are crucial for accurate results of the examined wave-body interaction scenarios.}, keywords = {CFD; potential flow; seakeeping; added resistance}, year = {2023}, eissn = {2077-1312} } @article{MTMT:33441192, title = {Hydrodynamic Modelling of Wave Overtopping over a Block-Covered Flood Defence}, url = {https://m2.mtmt.hu/api/publication/33441192}, author = {Barendse, Luuk and van Bergeijk, Vera M. and Chen, Weiqiu and Warmink, Jord J. and Mughal, Aroen and Hill, Dorian and Hulscher, Suzanne J. M. H.}, doi = {10.3390/jmse10010089}, journal-iso = {J MAR SCI ENG}, journal = {JOURNAL OF MARINE SCIENCE AND ENGINEERING}, volume = {10}, unique-id = {33441192}, abstract = {Wave overtopping can cause erosion on the landward slope due to high flow velocities and turbulence that cause high stresses on the cover. Innovative block revetments such as Grassblocks protect the subsoil of the dike against erosion. The blocks are permeable, which reduces the flow velocity and the pressures along the landward slope. The performance of these blocks is assessed in physical tests, which provides insights into the stability of the blocks. However, such experiments are expensive and accurate measurements are difficult due to highly turbulent conditions. Therefore, the goal of this study is to determine the hydrodynamic conditions at the dike cover caused by the wave run-up on the seaward slope and by the overtopping flow over the crest and landward slope. The geometry and wave conditions from the physical test at the Deltares Delta flume are implemented in an OpenFOAM(R) numerical model. Using the porousWaveFoam solver, a porous layer on the crest and landward slope is implemented, where the flow resistance of this porous layer largely depends on the resistance coefficients alpha [-] and beta [-]. The numerical model is calibrated based on resistance coefficients as introduced earlier in the literature, which showed that the resistance coefficients of alpha=500 and beta=2.0 performed best for the peak flow velocities and the peak pressures. The numerical model is evaluated by using these resistance coefficients in other time series of the physical tests. The evaluated model is then used to determine the hydrodynamic conditions on the landward slope, which showed that the pressure was the most influential hydrodynamic condition at the time of failure. Finally, the model showed that a porosity of n=0.6 and the porous layer thickness eta=36 mm reduced the peak pressure the most.}, keywords = {Computational fluid dynamics; hydraulic load; OpenFOAM; block revetments; permeable layer}, year = {2022}, eissn = {2077-1312}, orcid-numbers = {Barendse, Luuk/0000-0002-3274-1829; Chen, Weiqiu/0000-0003-2489-913X} } @article{MTMT:33441188, title = {Evaluation of Morison approach with CFD modelling on a surface-piercing cylinder towards the investigation of FOWT Hydrodynamics}, url = {https://m2.mtmt.hu/api/publication/33441188}, author = {Clement, Constance and Bozonnet, Pauline and Vinay, Guillaume and Pagnier, Philippe and Reveillon, Julien}, doi = {10.1016/j.oceaneng.2022.111042}, journal-iso = {OCEAN ENG}, journal = {OCEAN ENGINEERING}, volume = {251}, unique-id = {33441188}, issn = {0029-8018}, abstract = {To predict hydrodynamic forces on slender cylinders, Morison formula is commonly used. The expression is composed of two terms including an empirical drag and inertia coefficient. In the present study, a constrained cylinder subjected to regular waves is modelled using Computational Fluid Dynamics (CFD) and Morison coefficients are derived from the CFD loads. A numerical wave tank, including a surface-piercing cylinder, is implemented to generate, propagate and absorb waves in a controlled way. The cylinder is discretised into slices for each of which the Morison formulation is fitted to the CFD loads to determine Morison coefficients. Morison formulation is in very good agreement with the numerical load over the entire length of the cylinder, except for the slices near the free surface which are outside the applicability range of Morison formula. The loads near the free surface being negligible compared to the total load, the total theoretical load obtained reproduces well the experimental and the CFD loads. The CFD simulations proved to be a powerful tool to predict the wave loads and calibrate Morison coefficients. On this basis, the methodology will be extended to floating offshore wind platforms, combining several cylinders with different inclinations, sizes and positions.}, keywords = {Computational fluid dynamics; OpenFOAM; Numerical wave tank; floating offshore wind turbines; Surface-piercing cylinder; Morison empirical formula}, year = {2022}, eissn = {1873-5258}, orcid-numbers = {Reveillon, Julien/0000-0002-2289-3693} } @article{MTMT:33441193, title = {Numerical analysis of wave-structure interaction of regular waves with surface-piercing inclined plates}, url = {https://m2.mtmt.hu/api/publication/33441193}, author = {Cummins, C. P. and Scarlett, G. T. and Windt, C.}, doi = {10.1007/s40722-021-00219-6}, journal-iso = {J. Ocean Eng. Mar. Energy}, journal = {Journal of Ocean Engineering and Marine Energy}, volume = {8}, unique-id = {33441193}, issn = {2198-6444}, abstract = {The Mocean wave energy converter consists of two sections, hinged at a central location, allowing the device to convert energy from the relative pitching motion of the sections. In a simplified form, the scattering problem for the device can be modelled as monochromatic waves incident upon a thin, inclined, surface-piercing plate of length L' in a finite depth d' of water. In this paper, the flow past such a plate is solved using a Boundary Element Method (BEM) and Computational Fluid Dynamics (CFD). While the BEM solution is based on linear potential flow theory, CFD directly solves the Navier-Stokes equations. Problems of this type are known to exhibit near-perfect reflection (indicated by a reflection coefficient vertical bar R vertical bar approximate to 1) of waves at specific wavenumbers k'. In this paper, we show that the resonant motion of the fluid induces large hydrodynamic forces on the plate. Furthermore, we argue that this low-frequency resonance resembles Helmholtz resonance, and that Mocean's device being able to tune to these low frequencies does not act like an attenuator. For the case where the water is deep (d' >lambda'/2, where lambda' = 2 pi/k'), we find excellent agreement between our simulations and previous semi-analytical studies on the value of the resonant wave periods in deep water. We also find excellent agreement between the excitation forces on the plate computed using the BEM model, analytical results, and CFD for large inclination angles (alpha > 45 degrees). For alpha <= 15 degrees, both methods show the same trend, but the CFD predicts a significantly smaller peak in the excitation force compared with BEM, which we attribute to non-linear effects such as the non-linear Froude-Krylov force}, keywords = {reflection coefficient; CFD; Wave energy conversion; BEM; Inclined plate}, year = {2022}, pages = {99-115} } @article{MTMT:33588852, title = {The influence of the hull representation for modelling of primary ship waves with a shallow-water equation solver}, url = {https://m2.mtmt.hu/api/publication/33588852}, author = {Dempwolff, León-Carlos and Windt, Christian and Melling, Gregor and Martin, Tobias and Bihs, Hans and Holzwarth, Ingrid and Goseberg, Nils}, doi = {10.1016/j.oceaneng.2022.113163}, journal-iso = {OCEAN ENG}, journal = {OCEAN ENGINEERING}, volume = {266}, unique-id = {33588852}, issn = {0029-8018}, year = {2022}, eissn = {1873-5258}, orcid-numbers = {Dempwolff, León-Carlos/0000-0002-1154-6581; Windt, Christian/0000-0001-5301-6653; Melling, Gregor/0000-0003-2754-0341; Martin, Tobias/0000-0002-7810-2707; Bihs, Hans/0000-0002-8726-1283; Goseberg, Nils/0000-0002-1550-3001} } @article{MTMT:33441184, title = {Numerical Simulation of Irregular Breaking Waves Using a Coupled Artificial Compressibility Method}, url = {https://m2.mtmt.hu/api/publication/33441184}, author = {Dermatis, Athanasios and Ntouras, Dimitrios and Papadakis, George}, doi = {10.3390/fluids7070235}, journal-iso = {FLUIDS}, journal = {FLUIDS}, volume = {7}, unique-id = {33441184}, issn = {2311-5521}, abstract = {Wave breaking is widely recognized as a very challenging phenomenon to emulate using numerical/computational methods. On that condition, the transition from modelling regular to irregular breaking waves is not trivial. Even though some issues are surpassed in CFD simulations, there still are two substantial problems to account for. The first one entails the proper generation of irregular waves in a numerical wave tank, while the second is the introduction of the turbulent regime of breaking in the solver. The present work addresses these two problems by employing the Stabilized k-omega SST model for turbulence closure and by proposing an efficient and accurate method for irregular wave generation. Apart from that, an artificial compressibility method is used for coupling the system of equations, which solves these equations in a non-segregated manner and overcomes problems pertaining to the existence of the interface in free-surface flows. The methodology is validated through the test case of irregular wave propagation over a submerged breaker bar and a piecewise sloped bottom, indicating the ability of the method to capture irregular breaking wave phenomena. Simulations are in fair agreement with experimental data regarding energy spectra and free surface time-series, while results suggest that the known over-prediction of turbulent kinetic energy (TKE) is significantly constrained by the stabilized k-omega SST model.}, keywords = {CFD; Artificial compressibility; Navier-Stokes equations; irregular waves; wave breaking}, year = {2022}, orcid-numbers = {Papadakis, George/0000-0002-2742-5258} } @article{MTMT:33588829, title = {A Navier–Stokes numerical wave tank with a pressure-based relaxation zone method}, url = {https://m2.mtmt.hu/api/publication/33588829}, author = {De Vita, Francesco and Di Mascio, Andrea and Onorato, Miguel}, doi = {10.1016/j.oceaneng.2022.113207}, journal-iso = {OCEAN ENG}, journal = {OCEAN ENGINEERING}, volume = {266}, unique-id = {33588829}, issn = {0029-8018}, year = {2022}, eissn = {1873-5258}, orcid-numbers = {De Vita, Francesco/0000-0001-8616-269X; Di Mascio, Andrea/0000-0002-9772-3138} } @article{MTMT:33441186, title = {Experimental analysis and numerical simulation of wave overtopping on a fixed vertical cylinder under regular waves}, url = {https://m2.mtmt.hu/api/publication/33441186}, author = {Esteban, G. A. and Aristondo, A. and Izquierdo, U. and Blanco, J. M. and Perez-Moran, G.}, doi = {10.1016/j.coastaleng.2022.104097}, journal-iso = {COAST ENG}, journal = {COASTAL ENGINEERING}, volume = {173}, unique-id = {33441186}, issn = {0378-3839}, abstract = {Wave overtopping phenomenon affects relatively narrow offshore marine structures different from shoreline linear structures, where there is not defined a precise prediction methodology as it is the case of the behaviour at long coastal defences. In the present study a combined experimental and numerical approach has been followed to obtain an empirical relation that represents the relative overtopping discharge over a fixed vertical cylinder exposed to non-impulsive wave conditions. The phenomenon follows a Weibull type dependence on the relative freeboard in a similar way as the case of vertical walls but reporting a decreasing overtopping rate at higher freeboards. In addition, a direct linear relationship between the relative mean flow thickness computed at the centre of the circular crest of the cylinder and the relative overtopping discharge has been observed. This methodology may be used as an indirect cost-effective method to characterize experimentally the wave overtopping phenomenon in cylindrical structures of full-scale prototypes without the need of accumulating and characterising huge amounts of overtopped water volumes. The present study contains a systematic analysis of the dispersion obtained in the experimental and computational results to evaluate the performance attributed to the proposed empirical expressions.}, keywords = {Cylindrical structure; Physical model tests; wave overtopping; Numerical model tests; RANS-VOF}, year = {2022}, eissn = {1872-7379} } @article{MTMT:33542963, title = {A Review on the Modelling of Wave-Structure Interactions Based on OpenFOAM}, url = {https://m2.mtmt.hu/api/publication/33542963}, author = {Huang, Luofeng and Li, Yuzhu and Benites-Munoz, Daniela and Windt, Christian Windt and Feichtner, Anna and Tavakoli, Sasan and Davidson, Josh and Paredes, Ruben and Quintuna, Tadea and Ransley, Edward and Colombo, Marco and Li, Minghao and Cardiff, Philip and Tabor, Gavin}, doi = {10.51560/ofj.v2.65}, journal-iso = {OpenFOAM J}, journal = {OpenFOAM® Journal}, volume = {2}, unique-id = {33542963}, abstract = {The modelling of wave-structure interaction (WSI) has significant applications in understanding natural processes as well as securing the safety and efficiency of marine engineering. Based on the technique of Computational Fluid Dynamics (CFD) and the open-source simulation framework - OpenFOAM, this paper provides a state-of-the-art review of WSI modelling methods. The review categorises WSI scenarios and suggests their suitable computational approaches, concerning a rigid, deformable or porous structure in regular, irregular, non-breaking or breaking waves. Extensions of WSI modelling for wave-structure-seabed interactions and various wave energy converters are also introduced. As a result, the present review aims to help understand the CFD modelling of WSI and guide the use of OpenFOAM for target WSI problems.}, year = {2022}, eissn = {2753-8168}, pages = {116-142} } @{MTMT:33604773, title = {Monopile run-up study using Eulerian and Lagrangian numerical models}, url = {https://m2.mtmt.hu/api/publication/33604773}, author = {I., Herdayanditya and P., Rauwoens and G., Verao Fernandez and I., Martínez-Estévez and E., Lataire}, booktitle = {Proceedings. Trends in Renewable Energies Offshore}, unique-id = {33604773}, year = {2022}, pages = {1} } @article{MTMT:33399785, title = {Numerical modeling of extreme wave interaction with point-absorber using OpenFOAM}, url = {https://m2.mtmt.hu/api/publication/33399785}, author = {Katsidoniotaki, Eirini and Goteman, Malin}, doi = {10.1016/j.oceaneng.2021.110268}, journal-iso = {OCEAN ENG}, journal = {OCEAN ENGINEERING}, volume = {245}, unique-id = {33399785}, issn = {0029-8018}, abstract = {Extreme waves are critical for the WEC's development. CFD toolboxes have been widely used in the simulation of extreme waves-structure interaction. However, the quality of the mesh is a sensitive issue; the WEC's large response can lead to mesh deformation and subsequent numerical instability. In this paper, 100-year extreme waves are chosen from the environmental contour of the Humboldt Bay site in California, and their interaction with the WEC is modeled using the open-source CFD software OpenFOAM. The overset mesh technique is an advanced method recently available in OpenFOAM, able to handle great body motions. Here, the overset method is utilized and compared with the commonly used morphing method. The two methods provide equivalent results, but the latter is prone to the mesh deformation and fails to complete the simulations. Regarding the impact of extreme waves on WECs, the results further show that the combination of wave height and steepness is critical; i.e., the 100-year wave height does not necessarily result in the maximum forces, but rather steeper sea states tend to contribute in higher wave loadings. Additionally, the WEC is studied for 40% higher generator's damping, as it is a common control strategy during the harsh environmental conditions.}, keywords = {Overset mesh; Wave energy converter; Extreme waves; 100-year return period; Point-absorber; OpenFOAMv1906}, year = {2022}, eissn = {1873-5258}, orcid-numbers = {Goteman, Malin/0000-0001-9213-6447} } @article{MTMT:33399762, title = {A model predictive control (MPC)-integrated multiphase immersed boundary (IB) framework for simulating wave energy converters (WECs)}, url = {https://m2.mtmt.hu/api/publication/33399762}, author = {Khedkar, Kaustubh and Bhalla, Amneet Pal Singh}, doi = {10.1016/j.oceaneng.2022.111908}, journal-iso = {OCEAN ENG}, journal = {OCEAN ENGINEERING}, volume = {260}, unique-id = {33399762}, issn = {0029-8018}, abstract = {In this work, we present a novel MPC-integrated multiphase IB framework that can compute the optimal energy-maximizing control force "on-the-fly"by dynamically interacting with a high-fidelity numerical wave tank (NWT). The computational model closely mimics the working setup of the device at its site of operation. Due to the requirement of solving a constrained optimization problem at each time step of the IB simulation, the MPC algorithm utilizes a low-dimensional dynamical model of the device that is based on the linear potential theory (LPT). The multiphase IB solver, on the other hand, is based on the high-dimensional fictitious domain Brinkman penalization (FD/BP) method, which fully-resolves the hydrodynamic non-linearities associated with the wave-structure interaction (WSI). A time-series forecasting auto-regressive model is implemented that predicts wave heights (from the past NWT data) to estimate the future wave excitation/Froude-Krylov forces for the MPC algorithm. Moreover, we also experiment with non-linear Froude-Krylov (NLFK) forces for the first time in an MPC formulation. The NLFK forces are computed efficiently using a static Cartesian grid, in which the WEC geometry is implicitly represented by a signed distance function. Under varying sea conditions, the predictions of the MPC-integrated multiphase IB solver are compared to the widely popular LPT-based solvers. In agitated sea conditions and/or under aggressive control, the LPT-based WSI solvers produce too optimistic (and misleading) power output values. Overall, six WSI/MPC solver combinations are compared for a heaving vertical cylinder to determine the reasons for discrepancies between high-and low-fidelity predictions. We also determine the pathway of energy transfer from the waves to the power take-off (PTO) system and verify the relationships using IB simulations. Additionally, three different sea states are simulated within the IB simulation to test the adaptive capability of MPC for WECs. MPC is demonstrated to adapt to changing sea conditions and find the optimal solution for each sea state.The interaction between the distributed-memory parallel multiphase IB solver (written in C++) and the serial MPC solver (written in MATLAB) is fully described to facilitate reproducibility. A bespoke communication layer between the two solvers is developed, which can be easily modified by the WEC community to experiment with other optimal controllers and computational fluid dynamics (CFD) solvers. All codes for this work are made open-source for pedagogical and research purposes.}, keywords = {optimal control; CFD; Adaptive mesh refinement; Level set method; wave-structure interaction; Brinkman penalization method; Ocean energy}, year = {2022}, eissn = {1873-5258} } @article{MTMT:33441189, title = {Simulation of free-surface flows using the Lattice Boltzmann method with the AMR technique}, url = {https://m2.mtmt.hu/api/publication/33441189}, author = {Liu, Zhengliang and Feng, Xingya}, doi = {10.1177/09544062211065629}, journal-iso = {P I MECH ENG C-J MEC}, journal = {PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART C-JOURNAL OF MECHANICAL ENGINEERING SCIENCE}, unique-id = {33441189}, issn = {0954-4062}, abstract = {High resolution grids are generally preferred near the free surface to capture desired phenomena. In the present paper, an adaptive mesh refinement (AMR) framework based on the hash table data structure is introduced to the lattice Boltzmann method (LBM). The AMR refinement criterion is based on the movement of the free surface captured through interface nodes. The performance of the AMR-based LBM solver is analyzed through several benchmark cases. Results show that the proposed numerical framework can properly track the free surface with a spatial convergence rate between the first and second order. In addition, the AMR framework is of benefit to efficiently simulating free-surface flows since it requires much less nodes to achieve high resolution near the interface.}, keywords = {lattice Boltzmann method; Adaptive mesh refinement; free surface}, year = {2022}, eissn = {2041-2983}, orcid-numbers = {Liu, Zhengliang/0000-0002-3381-871X; Feng, Xingya/0000-0001-9787-2611} } @article{MTMT:33441183, title = {An improved wavemaker velocity boundary condition for generating realistic waves in the numerical wave tank}, url = {https://m2.mtmt.hu/api/publication/33441183}, author = {Lv, Chaofan and Zhao, Xizeng and Li, Mingchang and Xie, Yulin}, doi = {10.1016/j.oceaneng.2022.112188}, journal-iso = {OCEAN ENG}, journal = {OCEAN ENGINEERING}, volume = {261}, unique-id = {33441183}, issn = {0029-8018}, abstract = {Wavemaker velocity boundary condition method is one of the most common methods for wave generation in numerical wave tanks (NWTs). Traditional wavemaker velocity boundary condition (TWVBC) makes mass flux at the wavemaker boundary nonconservation, and produces a net mass transport flow in the NWT. In this paper, an improved wavemaker velocity boundary condition (IWVBC) is proposed by adding a reverse current at the wavemaker boundary. Through theoretical analysis, the phenomenon of mass nonconservation of regular and random waves is studied, and different modes of the net mass transport are found. Then, the IWVBC and TWVBC are applied to a computational fluid dynamics (CFD) model and the corresponding results are compared with reference data. The results show that the IWVBC can effectively maintain the mass conservation of the NWT and avoid the occurrence of net mass transport and the rise of mean water level. Furthermore, CFD results are basically consistent with the experimental law of wave profile, velocity and mass transport, which indicates that the IWVBC can reproduce realistic wave propagation characteristics in a NWT.}, keywords = {WAVE GENERATION; Numerical wave tank; Velocity boundary condition; Mass nonconservation; Net mass transport}, year = {2022}, eissn = {1873-5258}, orcid-numbers = {Zhao, Xizeng/0000-0002-1392-139X} } @article{MTMT:33399782, title = {Development of a CFD-based numerical wave tank of a novel multipurpose wave energy converter}, url = {https://m2.mtmt.hu/api/publication/33399782}, author = {Oliveira, D. and de Almeida, J. P. P. G. Lopes and Santiago, A. and Rigueiro, C.}, doi = {10.1016/j.renene.2022.08.103}, journal-iso = {RENEW ENERGY}, journal = {RENEWABLE ENERGY}, volume = {199}, unique-id = {33399782}, issn = {0960-1481}, abstract = {The development of new wave energy converters usually involves small-scale experiments in physical wave tanks. The jump to physical models at larger scales is an expensive and time-consuming process that can be supported by computational fluid dynamics (CFD) models. Using the CFD approach, it is possible to numerically simulate complex flows with high accuracy, once validation with experimental data has been carried out. This article describes an approach based on guidelines taken from the literature and adopted to develop and explore the capabilities of a CFD-based numerical wave tank for a novel multipurpose wave energy converter, REEFS. An incremental validation procedure, using experimental data collected with a piston-type wave tank, was adopted; the procedure began with wave-only tests which were followed by wave-structure interaction tests. Snapshots of numerical and experimental approaches were used to analyse fluid flow in the envelope of the REEFS converter. The results demonstrate that the CFD-based numerical wave tank model can adequately simulate the global wave surface profile, as well as local complex phenomena, such as the Venturi aspiration effect, that typically occur near the exterior stay vanes of the device. The results encourage the adoption of this model for future REEFS analysis.}, keywords = {CFD-based numerical wave tank; Physical wave tank; REEFS multipurpose Wave energy converter; Wave -structure interaction}, year = {2022}, eissn = {1879-0682}, pages = {226-245} } @article{MTMT:32746766, title = {Optimizing wave generation and wave damping in 3D-flow simulations with implicit relaxation zones}, url = {https://m2.mtmt.hu/api/publication/32746766}, author = {Perić, Robinson and Vukčević, Vuko and Abdel-Maksoud, Moustafa and Jasak, Hrvoje}, doi = {10.1016/j.coastaleng.2021.104035}, journal-iso = {COAST ENG}, journal = {COASTAL ENGINEERING}, volume = {171}, unique-id = {32746766}, issn = {0378-3839}, year = {2022}, eissn = {1872-7379}, orcid-numbers = {Perić, Robinson/0000-0002-6537-2222; Jasak, Hrvoje/0000-0002-8170-5787} } @article{MTMT:33441181, title = {Numerical Analysis of a Horizontal Pressure Differential Wave Energy Converter}, url = {https://m2.mtmt.hu/api/publication/33441181}, author = {Renganathan, Manimaran and Hossain, Mamdud}, doi = {10.3390/en15207513}, journal-iso = {ENERGIES}, journal = {ENERGIES}, volume = {15}, unique-id = {33441181}, issn = {1996-1073}, abstract = {CFD modeling of an innovative wave energy device has been carried out in this study. OpenFoam wave modeling solver interFoam has been employed in order to investigate the energy extraction capability of the wave energy device. The innovative concept is based on utilizing the pressure differential under the crest and trough of a wave to drive flow through a pipe. The simulated surface elevation of a wave has been validated against the reported wave tank experimental data in order to provide confidence in the modeling outcome. Further, simulations have been carried out with the device placed near to the bottom of the numerical wave tank in order establish the energy extraction potential. The simulation results confirm that effective power can be generated from the wave energy device. The efficiency of the device decreases with the increase in wave height, although it increases with the wave period. Higher power-take off (PTO) damping is also beneficial in extracting increased energy from waves.}, keywords = {Computational fluid dynamics; Pipe; differential pressure; wave tank; orifice geometry}, year = {2022}, eissn = {1996-1073}, orcid-numbers = {Hossain, Mamdud/0000-0002-9492-2721} } @article{MTMT:32746798, title = {Application of a Moving Particle Semi-Implicit Numerical Wave Flume (MPS-NWF) to model design waves}, url = {https://m2.mtmt.hu/api/publication/32746798}, author = {Renzi, E. and Dias, F.}, doi = {10.1016/j.coastaleng.2021.104066}, journal-iso = {COAST ENG}, journal = {COASTAL ENGINEERING}, volume = {172}, unique-id = {32746798}, issn = {0378-3839}, year = {2022}, eissn = {1872-7379}, orcid-numbers = {Renzi, E./0000-0002-1459-5565} } @article{MTMT:33406371, title = {Numerical study on wave-structure interaction based on functional decomposition method}, url = {https://m2.mtmt.hu/api/publication/33406371}, author = {Yu, Jiawei and Yao, Chaobang and Liu, Liwei and Dong, Guohua and Zhang, Zhiguo}, doi = {10.1016/j.oceaneng.2022.113067}, journal-iso = {OCEAN ENG}, journal = {OCEAN ENGINEERING}, volume = {266}, unique-id = {33406371}, issn = {0029-8018}, abstract = {A hybrid approach of potential and viscous flows for wave-structure interaction is developed to improve the efficiency. The total field of velocity, pressure and free surface elevation in the computational domain is decomposed into an incident field and a complementary field. For the incident wave field, the viscosity of fluid is neglected and the solution satisfies the incompressible Euler equations. With respect to the complementary field, the variables are governed by the Spectral Wave Explicit Navier-Stokes Equations (SWENSE). Furthermore, the adapted single-phase level-set model is used to capture the free surface and the dynamic structured overset technology is used to handle the large-amplitude motions of the structure. Based on this hybrid approach, an in-house code HUST-SWENSE is developed and systematic validations are carried out. The influences of the grid size, time step, wave steepness, treatment of the ship velocity and the method to obtain velocity derivatives on the regular wave propagation are first discussed in detail, along with the investigations on the performance of the HUST-SWENSE. The present method is then used to study the wave induced forces and motions for the structures with/without velocity, including a zero-velocity surface-piercing column and three ships with different veloc-ities. Three typical ships, including the low-speed tanker ship KVLCC2 (Fr = 0.142), the medium-speed container ship KCS (Fr = 0.26) and the high-speed surface combatant DTMB5512 (Fr = 0.41), are simulated in waves with two-degree-of-freedom (2DOF). Numerical results indicate that HUST-SWENSE is efficient and accurate for the simulation of the wave propagation and wave-structure interaction.}, keywords = {wave-structure interaction; Functional decomposition model; SWENSE; Hybrid approach of potential and viscous flows; Dynamic overset technology}, year = {2022}, eissn = {1873-5258} } @article{MTMT:32404400, title = {Assessing focused wave impacts on floating wave energy converters using OpenFOAM}, url = {https://m2.mtmt.hu/api/publication/32404400}, author = {Brown, Scott Andrew and Ransley, Edward Jack and Greaves, Deborah M.}, doi = {10.1680/jencm.19.00036}, journal-iso = {P I CIVIL ENG-ENG COMPUT MECH}, journal = {PROCEEDINGS OF THE INSTITUTION OF CIVIL ENGINEERS-ENGINEERING AND COMPUTATIONAL MECHANICS}, volume = {174}, unique-id = {32404400}, issn = {1755-0777}, abstract = {This study considers focused wave interactions with floating wave energy converters and represents an individual contribution to the CCP-WSI blind test series 2, in which the submitted results are compared against both physical and alternative numerical solutions for varying wave steepness achieved through changes in peak frequency. Reducing the time taken to provide reliable results is critical if computational fluid dynamics (CFD) is to become a routine design tool for offshore renewable energy devices. This can potentially be achieved by simplifying simulation set-up, and hence reduce the required man-hours, through standardised 'best practice' procedures. In order to achieve this, it is essential that the limitations of a numerical tool are well understood, and minimised. Therefore, this study aims to quantify the numerical reproduction of the focused wave event, and the motion of two different geometries predicted using a commonly used CFD methodology with waves generation achieved by way of linear superposition. The results imply that the error in peak values of heave and empty tank surface elevation are comparable, but the peak surge and pitch are substantially larger. This is likely due to a combination of numerical modelling errors, which must be addressed in future study.}, keywords = {Renewable energy; Computational mechanics; hydraulics & hydrodynamics}, year = {2021}, eissn = {1755-0785}, pages = {4-18} } @inbook{MTMT:31843113, title = {Wave generation and absorption techniques}, url = {https://m2.mtmt.hu/api/publication/31843113}, author = {Dimakopoulos, Aggelos and Higuera, Pablo}, booktitle = {Advanced Numerical Modelling of Wave Structure Interactions}, unique-id = {31843113}, year = {2021}, pages = {1-35} } @article{MTMT:32406789, title = {Response of Point-Absorbing Wave Energy Conversion System in 50-Years Return Period Extreme Focused Waves}, url = {https://m2.mtmt.hu/api/publication/32406789}, author = {Katsidoniotaki, Eirini and Nilsson, Erik and Rutgersson, Anna and Engstrom, Jens and Goteman, Malin}, doi = {10.3390/jmse9030345}, journal-iso = {J MAR SCI ENG}, journal = {JOURNAL OF MARINE SCIENCE AND ENGINEERING}, volume = {9}, unique-id = {32406789}, abstract = {This work evaluates the survivability of a point-absorbing wave energy converter at sea states along and inside the 50-year environmental contour for a selected-site in North Sea, by utilizing CFD simulations. Focused wave groups based on NewWave theory are used to model the extreme waves. The numerical breaking waves have been previously predicted by the analytical breaking criterion, showing that the latter provides an accurate estimate for the breaking state. The forces on key components of the device and the system's dynamics are studied and compared. Slamming loads are identified in the interaction with extreme waves, particularly with breaking waves, and compared with the analytical formulas for slamming estimation as suggested by industrial standards. Considering the extreme wave characteristics, the accompanied phenomena and the resulting WEC's response, this work contributes to the identification of the design-waves given the environmental contour of the selected site. The top-left side of the contour is identified as the more critical area as it consists of steep and high waves inducing significant nonlinear phenomena, resulting in high loads.}, keywords = {CFD; OpenFOAM; Overset mesh; Extreme waves; offshore WEC; breaking focused waves; slamming loads; 50-years return period}, year = {2021}, eissn = {2077-1312}, orcid-numbers = {Nilsson, Erik/0000-0003-3740-9507; Rutgersson, Anna/0000-0001-7656-1881; Goteman, Malin/0000-0001-9213-6447} } @article{MTMT:32406788, title = {The inertial sea wave energy converter (ISWEC) technology: Device-physics, multiphase modeling and simulations}, url = {https://m2.mtmt.hu/api/publication/32406788}, author = {Khedkar, Kaustubh and Nangia, Nishant and Thirumalaisamy, Ramakrishnan and Bhalla, Amneet Pal Singh}, doi = {10.1016/j.oceaneng.2021.108879}, journal-iso = {OCEAN ENG}, journal = {OCEAN ENGINEERING}, volume = {229}, unique-id = {32406788}, issn = {0029-8018}, abstract = {In this paper we investigate the dynamics of the inertial sea wave energy converter (ISWEC) device using fully-resolved computational fluid dynamics (CFD) simulations. Originally prototyped by the Polytechnic University of Turin, the device consists of a floating, boat-shaped hull that is slack-moored to the sea bed. Internally, a gyroscopic power take-off (PTO) unit converts the wave-induced pitch motion of the hull into electrical energy. The CFD model is based on the incompressible Navier-Stokes equations and utilizes the fictitious domain Brinkman penalization (FD/BP) technique to couple the device physics and water wave dynamics. A numerical wave tank is used to generate both regular waves based on fifth-order Stokes theory and irregular waves based on the JONSWAP spectrum to emulate realistic sea operating conditions. A Froude scaling analysis is performed to enable two- and three-dimensional simulations for a scaled-down (1:20) ISWEC model. It is demonstrated that the scaled-down 2D model is sufficient to accurately simulate the hull's pitching motion and to predict the power generation capability of the converter. A systematic parameter study of the ISWEC is conducted, and its optimal performance in terms of power generation is determined based on the hull and gyroscope control parameters. It is demonstrated that the device achieves peak performance when the gyroscope specifications are chosen based on the reactive control theory. It is shown that a proportional control of the PTO control torque is required to generate continuous gyroscopic precession effects, without which the device generates no power. In an inertial reference frame, it is demonstrated that the yaw and pitch torques acting on the hull are of the same order of magnitude, informing future design investigations of the ISWEC technology. Further, an energy transfer pathway from the water waves to the hull, the hull to the gyroscope, and the gyroscope to the PTO unit is analytically described and numerically verified. Additional parametric analysis demonstrates that a hull length to wavelength ratio between one-half and one-third yields high conversion efficiency (ratio of power absorbed by the PTO unit to wave power per unit crest width). Finally, device protection during inclement weather conditions is emulated by gradually reducing the gyroscope flywheel speed to zero, and the resulting dynamics are investigated.}, keywords = {Renewable energy; Adaptive mesh refinement; Level set method; Numerical wave tank; wave-structure interaction; Brinkman penalization method}, year = {2021}, eissn = {1873-5258}, orcid-numbers = {Bhalla, Amneet Pal Singh/0000-0002-0173-9881} } @article{MTMT:32406764, title = {Effects of a Bulbous Bow Shape on Added Resistance Acting on the Hull of a Ship in Regular Head Wave}, url = {https://m2.mtmt.hu/api/publication/32406764}, author = {Trung-Kien Le and Ngo Van He and Ngo Van Hien and Ngoc-Tam Bui}, doi = {10.3390/jmse9060559}, journal-iso = {J MAR SCI ENG}, journal = {JOURNAL OF MARINE SCIENCE AND ENGINEERING}, volume = {9}, unique-id = {32406764}, abstract = {In this study, the effect of bow shape on resistance acting on a hull in regular head waves was investigated by applying a commercial Computational Fluid Dynamics (CFD) code. For this purpose, the hydrodynamic performance as well as the resistance of ships with blunt and bulbous bows were simulated. By analyzing the obtained CFD simulation results, the effects of the bow shape on the hydrodynamic performance and resistance of the ships were found. A new bulbous bow shape with drastically reduced added resistance acting on the hull in waves is proposed. Finally, the obtained CFD results for the hydrodynamic performance of ships are presented.}, keywords = {RESISTANCE; hydrodynamic; Hull; CFD; regular head waves; bulbous bow}, year = {2021}, eissn = {2077-1312} } @article{MTMT:31798371, title = {Assessing the validity of regular wave theory in a short physical wave flume using particle image velocimetry}, url = {https://m2.mtmt.hu/api/publication/31798371}, author = {Windt, Christian and Untrau, Alix and Davidson, Joshua Patrick and Ransley, Edward J. and Greaves, Deborah M. and Ringwood, John V.}, doi = {10.1016/j.expthermflusci.2020.110276}, journal-iso = {EXP THERM FLUID SCI}, journal = {EXPERIMENTAL THERMAL AND FLUID SCIENCE}, volume = {121}, unique-id = {31798371}, issn = {0894-1777}, year = {2021}, eissn = {1879-2286} } @article{MTMT:32404395, title = {Numerical analysis of the hydrodynamic scaling effects for the Wavestar wave energy converter}, url = {https://m2.mtmt.hu/api/publication/32404395}, author = {Windt, Christian and Davidson, Joshua Patrick and Ringwood, John V}, doi = {10.1016/j.jfluidstructs.2021.103328}, journal-iso = {J FLUID STRUCT}, journal = {JOURNAL OF FLUIDS AND STRUCTURES}, volume = {105}, unique-id = {32404395}, issn = {0889-9746}, abstract = {Scaled model tests are an important step during the research and development of wave energy converters (WECs). While such scaled model tests in physical wave tanks are prone to undesired scaling effects due to e.g. mechanical artefacts and/or fluid effects, numerical wave tanks (NWTs) provide excellent tools for the analysis of WECs across a range of scales, overcoming the limitations of the physical test environment. Simultaneous scaling based on the Froude and Reynolds number is achievable in physical wave tanks only with significant effort, whereas NWTs allow the adjustment of fluid properties, such as viscosity, in an easy manner, thereby catering for Froude and Reynolds similarity. This study exploits the capabilities of a high-fidelity, computational fluid dynamics based, NWT and investigates the hydrodynamic scaling effects for the heaving buoy Wavestar WEC. Various test cases, relevant for WEC applications and with progressively increasing complexity, are considered to develop a comprehensive understanding of the scaling effects. Results show that significant scaling effects occur for the viscous component of the hydrodynamic loads on the WEC hull, while the system dynamics and total (viscous + pressure) loads are relatively unaffected by scaling effects. (C) 2021 The Author(s). Published by Elsevier Ltd.}, keywords = {OpenFOAM; RANS; Numerical wave tank; Scaling effect; Wavestar}, year = {2021}, eissn = {1095-8622}, orcid-numbers = {Ringwood, John V/0000-0003-0395-7943} } @article{MTMT:32404391, title = {Reactive control of wave energy devices-the modelling paradox}, url = {https://m2.mtmt.hu/api/publication/32404391}, author = {Windt, Christian and Faedo, Nicolas and Penalba, Markel and Dias, Frederic and Ringwood, John V.}, doi = {10.1016/j.apor.2021.102574}, journal-iso = {APPL OCEAN RES}, journal = {APPLIED OCEAN RESEARCH}, volume = {109}, unique-id = {32404391}, issn = {0141-1187}, abstract = {The implementation of energy maximising control systems (EMCSs) in wave energy converter (WEC) devices is an important step towards commercially viable operation of WECs. During the design stage of such EMCSs, linear hydrodynamic models are commonly used and are, in fact, the most viable option due to the real?time computational requirements of optimisation routines associated with energy-maximising optimal control tech-niques. However, the objective function of EMCSs, i.e. maximising the generated power by exaggerating WEC motion, inherently violates the underlying assumption of the linear hydrodynamic control design models, i.e. small amplitude device motion (compared to the device dimensions). Consequently, the linear models, used as a basis for EMCSs, in fact conspire to violate the very assumption upon which they were built -hence leading to a modelling paradox. It is important to evaluate WEC controllers in realistic physical or numerical environments, to gain knowledge of the disparity between the performance prediction from the EMCS design and performance evaluation models. This paper presents a comprehensive assessment of the performance prediction by a linear and non?linear hydrodynamic model of three different EMCSs, implemented in two different WEC structures, in an attempt to quantify the severity of this modelling disparity, or paradox.}, keywords = {optimal control; Wave energy; CFD; OpenFOAM; Moment-Matching}, year = {2021}, eissn = {1879-1549}, orcid-numbers = {Penalba, Markel/0000-0002-8396-7334; Dias, Frederic/0000-0002-5123-4929} } @article{MTMT:31801794, title = {Some recent fluid-structure interaction approaches for the wave current behaviour with offshore structures}, url = {https://m2.mtmt.hu/api/publication/31801794}, author = {Ahmed, M. and Nizamani, Z. and Nakayama, A. and Osman, M.}, doi = {10.37934/cfdl.12.9.1526}, journal-iso = {CFD Letters}, journal = {CFD Letters}, volume = {12}, unique-id = {31801794}, issn = {2180-1363}, year = {2020}, pages = {15-26} } @article{MTMT:31491417, title = {Quantifying the Predictive Capability of OpenFOAM 5.0: Focused Wave Impacts with Floating Bodies}, url = {https://m2.mtmt.hu/api/publication/31491417}, author = {Brown, Scott Andrew and Ransley, Edward Jack and Musiedlak, Pierre-Henri and Greaves, Deborah}, doi = {10.17736/ijope.2020.jc779}, journal-iso = {INT J OFFSHORE POLAR}, journal = {INTERNATIONAL JOURNAL OF OFFSHORE AND POLAR ENGINEERING}, volume = {30}, unique-id = {31491417}, issn = {1053-5381}, abstract = {This work concerns the quantification of numerical accuracy for focused wave interactions with floating structures, using results obtained via a commonly used computational fluid dynamics (CFD) and linear wave superposition approach. It represents an individual contribution to the CCP-WSI Blind Test Series 3, where numerical predictions for a structure's motion are submitted for comparison with physical data, without prior access to this data. An estimation of accuracy based on the reproduction of physical empty tank data, and previous experience, is compared with the observed error in the structure's motion. The results imply that the error in peak values of heave and empty tank surface elevation are comparable, but the peak surge and pitch are substantially larger. This is likely due to a combination of numerical modelling errors, although numerical uncertainty must also be reduced in order to fully assess the problem.}, keywords = {Numerical modelling; UNCERTAINTY; extreme events; Error estimation; CCP-WSI Blind Test Series 3; WECs}, year = {2020}, eissn = {1053-5381}, pages = {20-27} } @inbook{MTMT:31801972, title = {Numerical Wave Tank Including a Fixed Vertical Cylinder Subjected to Waves, Towards the Investigation of Floating Offshore Wind Turbine Hydrodynamics}, url = {https://m2.mtmt.hu/api/publication/31801972}, author = {Clément, Constance and Bozonnet, Pauline and Vinay, Guillaume and Borras Nadal, Adria and Pagnier, Philippe and Réveillon, Julien}, booktitle = {Proceedings of the ASME 39th International Conference on Ocean, Offshore and Arctic Engineering (OMAE2020)}, doi = {10.1115/OMAE2020-18797}, unique-id = {31801972}, year = {2020} } @article{MTMT:31491403, title = {Efficient Nonlinear Hydrodynamic Models for Wave Energy Converter Design-A Scoping Study}, url = {https://m2.mtmt.hu/api/publication/31491403}, author = {Davidson, Joshua Patrick and Costello, Ronan}, doi = {10.3390/jmse8010035}, journal-iso = {J MAR SCI ENG}, journal = {JOURNAL OF MARINE SCIENCE AND ENGINEERING}, volume = {8}, unique-id = {31491403}, abstract = {This review focuses on the most suitable form of hydrodynamic modeling for the next generation wave energy converter (WEC) design tools. To design and optimize a WEC, it is estimated that several million hours of operation must be simulated, perhaps one million hours of WEC simulation per year of the R&D program. This level of coverage is possible with linear potential flow (LPF) models, but the fidelity of the physics included is not adequate. Conversely, while Reynolds averaged Navier-Stokes (RANS) type computational fluid dynamics (CFD) solvers provide a high fidelity representation of the physics, the increased computational burden of these models renders the required amount of simulations infeasible. To scope the fast, high fidelity options, the present literature review aims to focus on what CFD theories exist intermediate to LPF and RANS as well as other modeling options that are computationally fast while retaining higher fidelity than LPF.}, keywords = {hydrodynamics; Wave energy; nonlinear; CFD}, year = {2020}, eissn = {2077-1312}, orcid-numbers = {Davidson, Joshua Patrick/0000-0001-5966-4272} } @book{MTMT:31833460, title = {Roll Damping Simulations of an Offshore Heavy Lift DP3 Installation Vessel Using the CFD Toolbox OpenFOAM}, url = {https://m2.mtmt.hu/api/publication/31833460}, author = {Devolder, Brecht and Stempinski, Florian and Mol, Arjan and Rauwoens, Pieter}, publisher = {American Society of Mechanical Engineers (ASME)}, volume = {84409}, unique-id = {31833460}, year = {2020}, pages = {V008T08A045} } @article{MTMT:31493005, title = {Fuzzy Control of Waves Generation in a Towing Tank}, url = {https://m2.mtmt.hu/api/publication/31493005}, author = {Drzewiecki, Marcin and Guzinski, Jaroslaw}, doi = {10.3390/en13082049}, journal-iso = {ENERGIES}, journal = {ENERGIES}, volume = {13}, unique-id = {31493005}, issn = {1996-1073}, abstract = {This paper presents the results of research related to the transformation of electrical energy into potential and kinetic energy of waves generated on the water surface. The waves are generated to model the environmental conditions for the needs of the model tests. The model tests are performed on model-scale objects to predict the features of full-scale maritime objects. It is done to improve human safety and the survivability of constructions. Electrical energy is transformed into the energy of the water waves using a wave maker. The wave maker considered is a facility with an electrohydraulic drive and an actuator submerged into the water. The actuator movement results in the waves being mechanically-generated in accordance with the wave maker theory. The study aimed to investigate the advantage of the newly implemented fuzzy-logic controller over the hitherto cascading proportional-integral controllers of the wave maker actuator. The research was focused on experimental investigation of the transformation process outcomes harvested under the fuzzy-logic controller, versus the cascading proportional-integral controllers. The waves were generated and measured in the real towing tank, located in the Maritime Advanced Research Centre (CTO S.A.). The investigation confirmed the advantage of the fuzzy-logic controller. It provides more accurate transformation of energy into the desired form of the water waves of specified parameters-frequency and amplitude-and more flat amplitude-frequency characteristic of the transformation process.}, keywords = {fuzzy control; Wave energy; WAVE GENERATION; Towing tank; energy transformation; model tests; wave maker}, year = {2020}, eissn = {1996-1073}, orcid-numbers = {Drzewiecki, Marcin/0000-0001-7644-3594} } @misc{MTMT:31843108, title = {On CFD Numerical Wave Tank Simulations: Static-Boundary Wave Absorption Enhancement Using a Geometrical Approach}, url = {https://m2.mtmt.hu/api/publication/31843108}, author = {Gamaleldin, Muhannad W. and Babanin, Alexander V. and Chabchoub, Amin}, unique-id = {31843108}, year = {2020}, pages = {1-23} } @article{MTMT:31737920, title = {Validation of RANS Modelling for Wave Interactions with Sea Dikes on Shallow Foreshores Using a Large-Scale Experimental Dataset}, url = {https://m2.mtmt.hu/api/publication/31737920}, author = {Gruwez, Vincent and Altomare, Corrado and Suzuki, Tomohiro and Streicher, Maximilian and Cappietti, Lorenzo and Kortenhaus, Andreas and Troch, Peter}, doi = {10.3390/jmse8090650}, journal-iso = {J MAR SCI ENG}, journal = {JOURNAL OF MARINE SCIENCE AND ENGINEERING}, volume = {8}, unique-id = {31737920}, abstract = {In this paper, a Reynolds-averaged Navier-Stokes (RANS) equations solver, interFoam of OpenFOAM(R), is validated for wave interactions with a dike, including a promenade and vertical wall, on a shallow foreshore. Such a coastal defence system is comprised of both an impermeable dike and a beach in front of it, forming the shallow foreshore depth at the dike toe. This case necessitates the simulation of several processes simultaneously: wave propagation, wave breaking over the beach slope, and wave interactions with the sea dike, consisting of wave overtopping, bore interactions on the promenade, and bore impacts on the dike-mounted vertical wall at the end of the promenade (storm wall or building). The validation is done using rare large-scale experimental data. Model performance and pattern statistics are employed to quantify the ability of the numerical model to reproduce the experimental data. In the evaluation method, a repeated test is used to estimate the experimental uncertainty. The solver interFoam is shown to generally have a very good model performance rating. A detailed analysis of the complex processes preceding the impacts on the vertical wall proves that a correct reproduction of the horizontal impact force and pressures is highly dependent on the accuracy of reproducing the bore interactions.}, keywords = {VALIDATION; OpenFOAM; wave modelling; shallow foreshore; dike-mounted vertical wall; wave impact loads}, year = {2020}, eissn = {2077-1312}, orcid-numbers = {Altomare, Corrado/0000-0001-8817-0431; Suzuki, Tomohiro/0000-0002-6008-4440; Troch, Peter/0000-0003-3274-0874} } @article{MTMT:31801786, title = {Interaction effect between hull and accommodation on wind drag acting on a container ship}, url = {https://m2.mtmt.hu/api/publication/31801786}, author = {He, N.V. and Hien, N.V. and Truong, V.-T. and Bui, N.-T.}, doi = {10.3390/jmse8110930}, journal-iso = {J MAR SCI ENG}, journal = {JOURNAL OF MARINE SCIENCE AND ENGINEERING}, volume = {8}, unique-id = {31801786}, year = {2020}, eissn = {2077-1312} } @article{MTMT:31010549, title = {Enhancing active wave absorption in RANS models}, url = {https://m2.mtmt.hu/api/publication/31010549}, author = {Higuera, Pablo}, doi = {10.1016/j.apor.2019.102000}, journal-iso = {APPL OCEAN RES}, journal = {APPLIED OCEAN RESEARCH}, volume = {94}, unique-id = {31010549}, issn = {0141-1187}, year = {2020}, eissn = {1879-1549} } @book{MTMT:31833524, title = {Comparison of dynamic mesh methods in OpenFOAM for a WEC in extreme waves}, url = {https://m2.mtmt.hu/api/publication/31833524}, author = {Katsidoniotaki, E. and Göteman, M.}, publisher = {CRC Press}, unique-id = {31833524}, year = {2020}, pages = {214} } @article{MTMT:31801784, title = {Third-order generation of narrow-banded wave trains by a wavemaker}, url = {https://m2.mtmt.hu/api/publication/31801784}, author = {Khait, A.}, doi = {10.1016/j.oceaneng.2020.108200}, journal-iso = {OCEAN ENG}, journal = {OCEAN ENGINEERING}, volume = {218}, unique-id = {31801784}, issn = {0029-8018}, year = {2020}, eissn = {1873-5258} } @article{MTMT:30975724, title = {A critical comparison of excitation force estimators for wave-energy devices}, url = {https://m2.mtmt.hu/api/publication/30975724}, author = {Pena-Sanchez, Yerai and Windt, Christian and Davidson, Joshua Patrick and Ringwood, John V.}, doi = {10.1109/TCST.2019.2939092}, journal-iso = {IEEE T CONTR SYST T}, journal = {IEEE TRANSACTIONS ON CONTROL SYSTEMS TECHNOLOGY}, volume = {28}, unique-id = {30975724}, issn = {1063-6536}, year = {2020}, eissn = {1558-0865}, pages = {2263-2275} } @article{MTMT:31843095, title = {Development and validation of a numerical wave tank based on the Harmonic Polynomial Cell and Immersed Boundary methods to model nonlinear wave-structure interaction}, url = {https://m2.mtmt.hu/api/publication/31843095}, author = {Robaux, Fabien and Benoit, Michel}, doi = {10.1016/j.jcp.2021.110560}, journal-iso = {J COMPUT PHYS}, journal = {JOURNAL OF COMPUTATIONAL PHYSICS}, volume = {446}, unique-id = {31843095}, issn = {0021-9991}, year = {2020}, eissn = {1090-2716} } @article{MTMT:31798397, title = {Beyond VoF: alternative OpenFOAM solvers for numerical wave tanks}, url = {https://m2.mtmt.hu/api/publication/31798397}, author = {Schmitt, Pál and Windt, Christian and Davidson, Joshua Patrick and Ringwood, John V. and Whittaker, Trevor}, doi = {10.1007/s40722-020-00173-9}, journal-iso = {Journal of Ocean Engineering and Marine Energy}, journal = {Journal of Ocean Engineering and Marine Energy}, volume = {6}, unique-id = {31798397}, issn = {2198-6452}, year = {2020}, pages = {277-292} } @book{MTMT:31833458, title = {Analysis of Open-Source CFD Tools for Simulating Complex Hydrodynamic Problems}, url = {https://m2.mtmt.hu/api/publication/31833458}, author = {Siddiqui, Mohd Atif and Xu, Hui-li and Greco, Marilena and Colicchio, Giuseppina}, publisher = {American Society of Mechanical Engineers (ASME)}, unique-id = {31833458}, year = {2020} } @book{MTMT:31843097, title = {Towards a high-fidelity simulation environment for structural integrity assessment of floating wind energy platforms}, url = {https://m2.mtmt.hu/api/publication/31843097}, isbn = {9780367681319}, author = {Souto-Canteli, Iñigo and Penalba, Markel and Martinez-Agirre, Manex and Ezkurra, Mikel and Esnaola, Jon-Ander and Llavori, Iñigo and Aizpurua, Jose-Ignacio}, doi = {10.1201/9781003134572-83}, publisher = {CRC Press}, unique-id = {31843097}, year = {2020} } @article{MTMT:31801785, title = {A ghost-cell immersed boundary method for wave–structure interaction using a two-phase flow model}, url = {https://m2.mtmt.hu/api/publication/31801785}, author = {Tsai, Y.-S. and Lo, D.-C.}, doi = {10.3390/w12123346}, journal-iso = {WATER-SUI}, journal = {WATER}, volume = {12}, unique-id = {31801785}, year = {2020}, eissn = {2073-4441} } @article{MTMT:31798280, title = {Investigation of Turbulence Modeling for Point-Absorber-Type Wave Energy Converters}, url = {https://m2.mtmt.hu/api/publication/31798280}, author = {Windt, Christian and Davidson, Joshua Patrick and Ringwood, John}, doi = {10.3390/en14010026}, journal-iso = {ENERGIES}, journal = {ENERGIES}, volume = {14}, unique-id = {31798280}, issn = {1996-1073}, year = {2020}, eissn = {1996-1073} } @article{MTMT:30975717, title = {Validation of a CFD-based numerical wave tank model for the power production assessment of the wavestar ocean wave energy converter}, url = {https://m2.mtmt.hu/api/publication/30975717}, author = {Windt, Christian and Davidson, Joshua Patrick and Ransley, Edward J. and Greaves, Deborah and Jakobsen, Morten and Kramer, Morten and Ringwood, John V.}, doi = {10.1016/j.renene.2019.08.059}, journal-iso = {RENEW ENERGY}, journal = {RENEWABLE ENERGY}, volume = {146}, unique-id = {30975717}, issn = {0960-1481}, year = {2020}, eissn = {1879-0682}, pages = {2499-2516}, orcid-numbers = {Windt, Christian/0000-0001-5301-6653; Greaves, Deborah/0000-0003-3906-9630} } @article{MTMT:31708490, title = {Validation of a CFD-Based Numerical Wave Tank Model of the 1/20th Scale Wavestar Wave Energy Converter}, url = {https://m2.mtmt.hu/api/publication/31708490}, author = {Windt, Christian and Faedo, Nicolas and Garcia-Violini, Demian and Pena-Sanchez, Yerai and Davidson, Joshua Patrick and Ferri, Francesco and Ringwood, John V.}, doi = {10.3390/fluids5030112}, journal-iso = {FLUIDS}, journal = {FLUIDS}, volume = {5}, unique-id = {31708490}, issn = {2311-5521}, abstract = {Numerical wave tanks (NWTs) provide efficient test beds for the numerical analysis at various stages during the development of wave energy converters (WECs). To ensure the acquisition of accurate, high-fidelity data sets, validation of NWTs is a crucial step. However, using experimental data as reference during model validation, exact knowledge of all system parameters is required, which may not always be available, thus making an incremental validation inevitable. The present paper documents the numerical model validation of a 1/20 scale Wavestar WEC. The validation is performed considering different test case of increasing complexity: wave-only, wave excitation force, free decay, forced oscillation, and wave-induced motion cases. The results show acceptable agreement between the numerical and experimental data so that, under the well-known modelling constraints for mechanical friction and uncertainties in the physical model properties, the developed numerical model can be declared as validated.}, keywords = {model validation; CFD; OpenFOAM; Numerical wave tank; wave-structure interaction}, year = {2020}, orcid-numbers = {Windt, Christian/0000-0001-5301-6653} } @article{MTMT:31737915, title = {Wave-structure interaction of wave energy converters: a sensitivity analysis}, url = {https://m2.mtmt.hu/api/publication/31737915}, author = {Windt, Christian and Davidson, Joshua Patrick and Schmitt, Pal and Ringwood, John V}, doi = {10.1680/jencm.19.00033}, journal-iso = {P I CIVIL ENG-ENG COMPUT MECH}, journal = {PROCEEDINGS OF THE INSTITUTION OF CIVIL ENGINEERS-ENGINEERING AND COMPUTATIONAL MECHANICS}, volume = {173}, unique-id = {31737915}, issn = {1755-0777}, abstract = {Measurement uncertainties are inevitable during physical wave tank tests. Therefore, when validating a numerical wave tank against experiments, knowledge of the uncertainties in the physical experiments, and the sensitivity of the body dynamics to such uncertainties, is crucial. Specifically, the inertial properties, as well as the location of the centre of mass (CoM), which are challenging to measure accurately, can have a significant influence on the system dynamics. On the basis of test cases of the Collaborative Computational Project in Wave Structure Interaction Blind Test Series 2, this paper presents a sensitivity analysis of the agreement between experimental and numerical data sets to the quality of the incident, focused wave, as well as the inertial properties and the location of the CoM. A significant influence on the modelled system dynamics can be observed when changing the system parameters, resulting in a variation of the observed error of up to 80 percentage points for pitch motion.}, keywords = {Renewable energy; hydraulics & hydrodynamics; Offshore engineering}, year = {2020}, eissn = {1755-0785}, pages = {144-158}, orcid-numbers = {Schmitt, Pal/0000-0001-8455-952X} } @misc{MTMT:31010028, title = {Dynamic mesh motion in OpenFOAM for wave energy converter simulation}, url = {https://m2.mtmt.hu/api/publication/31010028}, author = {Davidson, Joshua Patrick and Karimov, Mirlan and Szelechman, Adam and Windt, Christian and Ringwood, John V}, unique-id = {31010028}, year = {2019} } @book{MTMT:31843107, title = {CFD simulations of a monopile installation from a floating vessel}, url = {https://m2.mtmt.hu/api/publication/31843107}, author = {Devolder, Brecht and Rauwoens, Pieter}, publisher = {14th OpenFOAM Workshop}, unique-id = {31843107}, year = {2019} } @misc{MTMT:31010541, title = {Validation of a roll decay test of an offshore installation vessel using OpenFOAM}, url = {https://m2.mtmt.hu/api/publication/31010541}, author = {Devolder, Brecht and Stempinski, Florian and Mol, Arjan and Rauwoens, Pieter}, unique-id = {31010541}, year = {2019} } @inproceedings{MTMT:31578606, title = {VALIDATION OF A ROLL DECAY TEST OF AN OFFSHORE INSTALLATION VESSEL USING OPENFOAM}, url = {https://m2.mtmt.hu/api/publication/31578606}, author = {Devolder, Brecht and Stempinskit, Florian and Molt, Arjan and Rauwoens, Pieter}, booktitle = {8th Conference on Computational Methods in Marine Engineering (Marine 2019)}, unique-id = {31578606}, abstract = {In this work, the offshore heavy lift DP2 jack-up vessel Innovation from the DEME group is studied using the Computational Fluid Dynamics (CFD) toolbox OpenFOAM. The two-phase Navier-Stokes fluid solver is coupled with a motion solver using a partitioned fluid structure interaction algorithm. Firstly, two dimensional numerical simulations of a cross-section of the hull are performed using two different mesh motion techniques: a mesh morphing method and an overset mesh method. Subsequently, the addition of a bilge keel pair on the hull is studied numerically by performing a two dimensional roll decay simulation. Finally, a three dimensional simulation is performed for a roll decay test and validated by using experimental data measured in the MARIN seakeeping and manoeuvring basin. As a first result, the coupled CFD motion solver proofs to be a promising toolbox for the study of fluid-structure interaction problems of realistic marine structures such as an offshore installation vessel.}, keywords = {Numerical modelling; CFD; OpenFOAM; Floating structures}, year = {2019}, pages = {670-681} } @misc{MTMT:31010553, title = {Development towards a nested hydrodynamic model for the numerical analysis of ocean wave energy systems}, url = {https://m2.mtmt.hu/api/publication/31010553}, author = {Kemper, Jost and Windt, Christian and Graf, Kai and Ringwood, J.}, unique-id = {31010553}, year = {2019} } @mastersthesis{MTMT:31010545, title = {Investigation of crown wall stability on top of rubble mound structures with OpenFOAM®}, url = {https://m2.mtmt.hu/api/publication/31010545}, author = {Nikolaos, Sigalas}, unique-id = {31010545}, year = {2019} } @article{MTMT:30975743, title = {The Efficient Application of an Impulse SourceWavemaker to CFD Simulations}, url = {https://m2.mtmt.hu/api/publication/30975743}, author = {Schmitt, Pal and Windt, Christian and Davidson, Joshua Patrick and Ringwood, John V and Whittaker, Trevor}, doi = {10.3390/jmse7030071}, journal-iso = {J MAR SCI ENG}, journal = {JOURNAL OF MARINE SCIENCE AND ENGINEERING}, volume = {7}, unique-id = {30975743}, year = {2019}, eissn = {2077-1312} } @misc{MTMT:30975758, title = {Contribution to the CCP-WSI Blind Test Series 2: CFD-based numerical wave tank experiments employing an impulse source wave maker}, url = {https://m2.mtmt.hu/api/publication/30975758}, author = {Windt, Christian and Davidson, Joshua Patrick and Schmitt, Pál and V. Ringwood, John}, unique-id = {30975758}, year = {2019} } @inproceedings{MTMT:31801797, title = {Contribution to the CCP-WSI Blind Test Series 3: Analysis of scaling effects of moored point-absorber wave energy converters in a CFD-based numerical wave tank}, url = {https://m2.mtmt.hu/api/publication/31801797}, author = {Windt, Christian and Ringwood, J.V. and Davidson, Joshua Patrick and Schmitt, Pal}, booktitle = {Proceedings of the International Offshore and Polar Engineering Conference}, unique-id = {31801797}, year = {2019}, pages = {3051-3058} } @article{MTMT:31011444, title = {Evaluation of the overset grid method for control studies of wave energy converters in OpenFOAM numerical wave tanks}, url = {https://m2.mtmt.hu/api/publication/31011444}, author = {Windt, Christian and Davidson, Joshua Patrick and Chandar, Dominic D. J. and Faedo, Nicolás and Ringwood, John V.}, doi = {10.1007/s40722-019-00156-5}, journal-iso = {Journal of Ocean Engineering and Marine Energy}, journal = {Journal of Ocean Engineering and Marine Energy}, volume = {5}, unique-id = {31011444}, issn = {2198-6452}, year = {2019}, pages = {55-70} } @inproceedings{MTMT:31578414, title = {On the importance of advanced mesh motion methods for WEC experiments in CFD-based numerical wave tanks}, url = {https://m2.mtmt.hu/api/publication/31578414}, author = {Windt, Christian and Davidson, Joshua Patrick and Chandar, Dominic and Ringwood, John V.}, booktitle = {8th Conference on Computational Methods in Marine Engineering (Marine 2019)}, unique-id = {31578414}, abstract = {For the economical operation of wave energy converts (WECs), energy maximising control systems (EMCSs) are included in the device design, introducing large structural motions. During the numerical modelling of WECs in CFD-based numerical wave tanks (NWTs), the structural motions must be explicitly accommodated in the finite volume domain. Using well known mesh morphing methods, large amplitude WEC oscillations may deteriorate the quality of the spatial discretisation, and push the NWT beyond the limits of numerical stability. To overcome this issue, advanced mesh motion methods, such as overset grids, have been developed; however, these methods are rarely used in numerical WEC experiments. To this end, the present paper aims to highlight the importance of advanced mesh motion methods, when modelling WECs under controlled conditions. To furthermore prove the feasibility of the overset method, implemented in the OpenFOAM framework, simulations of an uncontrolled WEC are performed, and results are compared to simulations using the mesh morphing method. It is shown that the overset method has potential to improve CFD-based models of controlled WECs, but, at the expense of increased computational cost.}, keywords = {control; OpenFOAM; Numerical wave tank; Mesh motion; Overset grids}, year = {2019}, pages = {145-156} } @misc{MTMT:31010566, title = {CFD simulations of a monopile installation from a floating vessel.}, url = {https://m2.mtmt.hu/api/publication/31010566}, unique-id = {31010566}, year = {2019} }