TY - CONF AU - Kalmár-Nagy, Tamás AU - Lelkes, János ED - Fleck, Norman TI - Spatiotemporal Patterns in a Hysteretic Relay Oscillator Chain T2 - 26th International Congress of Theoretical and Applied Mechanics, Program Book C1 - Daegu PY - 2024 SP - 290 UR - https://m2.mtmt.hu/api/publication/35306321 ID - 35306321 LA - English DB - MTMT ER - TY - CONF AU - Kalmár-Nagy, Tamás AU - Horváth, Dávid András TI - Numerical Hopf Normal Form for Delay Differential Equations T2 - Online Book of Abstracts of the 11th European Nonlinear Dynamics Conference (ENOC 2024) PY - 2024 UR - https://m2.mtmt.hu/api/publication/35295306 ID - 35295306 LA - English DB - MTMT ER - TY - CONF AU - Horváth, Dávid András AU - Kalmár-Nagy, Tamás TI - Numerical Hopf Normal Form for Ordinary Differential Equations T2 - Online Book of Abstracts of the 11th European Nonlinear Dynamics Conference (ENOC 2024) PY - 2024 UR - https://m2.mtmt.hu/api/publication/35295021 ID - 35295021 LA - English DB - MTMT ER - TY - CHAP AU - Balla, Esztella Éva AU - Kovács, Kinga Andrea AU - Lendvai, Bálint TI - Comparison of Vortex Detection Methods on the Numerical Simulation of Tip Leakage Flow of a Low-Speed Axial Fan T2 - ASME Turbo Expo 2024: Turbomachinery Technical Conference and Exposition PB - American Society of Mechanical Engineers CY - New York, New York SN - 9780791887981 PY - 2024 PG - 10 DO - 10.1115/GT2024-121322 UR - https://m2.mtmt.hu/api/publication/35202418 ID - 35202418 AB - The present paper investigates the capabilities of the Lagrangian-Averaged Vorticity Deviation (LAVD) vortex detection method for turbomachinery applications. The tip leakage vortex of a low-speed axial fan is identified with multiple vortex detection methods. The investigation is carried out on a numerical simulation of a ducted fan. The results from the LAVD method are compared with the outcomes of the following vortex detection techniques: Q criterion, VR helicity density, vortex core distance technique of Li and Carrica, and Banks’ vorticity predictor-pressure corrector vortex core identification method. The position and extension of the vortex region and the location of the vortex core line are considered during the comparison. The results show that the vortex region and core detected by the LAVD technique are in great accordance with the outcome of the other methods. Compared to other methods, the advantage of the LAVD technique is that its parameters can be objectively defined from geometrical features of the flow field, e.g., blade chord length. The LAVD is also able to detect the core and the perimeter of the vortex region. LA - English DB - MTMT ER - TY - CHAP AU - Daku, Gábor AU - Vad, János TI - Enhanced Modelling of the Phenomenon of Vortex Shedding From a Low-Speed Axial Flow Rotor Blade Profile T2 - ASME Turbo Expo 2024: Turbomachinery Technical Conference and Exposition PB - American Society of Mechanical Engineers CY - New York, New York SN - 9780791887981 PY - 2024 PG - 12 DO - 10.1115/GT2024-123991 UR - https://m2.mtmt.hu/api/publication/35194486 ID - 35194486 AB - The paper presents CFD case studies on vortex shedding from an asymmetric RAF-6E airfoil profile being a representative of low-speed axial fan rotor blades, for angles of attack of α = 0.0°...2.7°, and chord-based Reynolds numbers Rec = (0.6...1.0) · 105. The shed vortices were identified on the basis of Lagrangian-averaged vorticity deviation. An organized dataset has been established for a comprehensive overview of the profile vortex shedding (PVS) phenomenon, enabling order-of-magnitude estimation of data and trends related to the size, rotation, circulation, and travelling velocity of the vortices. Literature-based rotationally symmetric aerodynamic models, as well as a simplified description of source term of vortex sound were applied to the shed vortices. On this basis, an enhanced modelling of PVS has been carried out for a straightforward and yet adequate consideration of the concerted aerodynamic and aeroacoustic aspects of PVS. Such modelling can give a contribution to preliminary fan design by taking the effects of PVS into account on blade vibration and fan noise. LA - English DB - MTMT ER - TY - CHAP AU - Soós, Bálint AU - Tokaji, Kristóf AU - Horváth, Csaba TI - Development and Application of a Beamforming Method for Extracting the Tonal Noise Components of Counter-Rotating Open Rotors T2 - 30th AIAA/CEAS Aeroacoustics Conference (2024) PB - American Institute of Aeronautics and Astronautics (AIAA) CY - Reston (VA) SN - 9781624107207 PY - 2024 SP - 1 EP - 16 PG - 16 DO - 10.2514/6.2024-3102 UR - https://m2.mtmt.hu/api/publication/35071624 ID - 35071624 N1 - Conference code: 315009 Export Date: 9 September 2024 Funding details: European Commission, EC Funding details: Nemzeti Kutatási, Fejlesztési és Innovaciós Alap, NKFIA Funding details: Magyarország Kormánya, VEKOP-2.3.3-15-2017-00017, 143204 Funding details: Hungarian Scientific Research Fund, OTKA, K 22 Funding text 1: This project has been partially supported by the European Union and the Hungarian Government in the framework of Competitive Central-Hungary OP (Project ID: VEKOP-2.3.3-15-2017-00017). Project no. 143204 has been implemented with the support provided by the Ministry of Innovation and Technology of Hungary from the National Research, Development and Innovation Fund, financed under the OTKA K 22 funding scheme. Project no. TKP-6- 6/PALY-2021 has been implemented with the support provided by the Ministry of Culture and Innovation of Hungary from the National Research, Development and Innovation Fund, financed under the TKP2021-NVA funding scheme. AB - Counter-rotating open rotors (CROR) offer increased efficiency in alignment with modern environmental standards, making them promising alternatives to single-rotor engines. This efficiency could expand the use of electrically powered aircraft and enhance the operational range of multi-rotor drones. However, these engines have to undergo improvements, including reducing their prominent noise emission. The noise from these engines can be decomposed into tonal and broadband components, each with distinct spectral characteristics. The understanding and analysis of CROR noise-generation mechanisms is aided by beamforming, which enables the identification of noise source locations and intensities. However, simultaneously examining tonal and broadband components poses challenges, necessitating a means for isolating these noise components and investigating them separately. First, this investigation presents a further development of the double filtering method, which enables a more efficient means of isolating the broadband components of CROR for beamforming investigations. The further developed method reduces data loss during the data processing, resulting in a statistically equivalent broadband time-domain signal of better quality, which will be used for further analysis. The investigation then presents how cross-spectral matrix operations can be used to subtract the statistically equivalent broadband time-domain signal from the original signal, making it possible to isolate the tonal components and enhance the effectiveness of tonal noise source investigations. The investigation introduces the method on simulated datasets, after which the article presents the extracted tonal signal from CROR measurement data. LA - English DB - MTMT ER - TY - CONF AU - Kocsis, Bálint AU - Tokaji, Kristóf AU - Leiber, Robin AU - Probst, Matthias AU - Istók, Balázs AU - Zhang, Haitian AU - Pritz, Balázs AU - Horváth, Csaba TI - Development of a measurement methodology for the beamforming investigation of centrifugal fans T2 - 10th Berlin Beamforming Conference (BeBeC) C1 - Berlin-Adlershof T3 - Berlin Beamforming Conference (BeBeC) PY - 2024 PG - 14 UR - https://m2.mtmt.hu/api/publication/35071592 ID - 35071592 AB - The investigation of turbomachinery applications using beamforming technology is rather common in the aeroacoustics community, but usually restricted to the investigation of axial flow turbomachinery. This investigation presents the development of a measurement setup and beamforming methodology that enables the investigation of centrifugal turbomachinery. A test setup utilizing Acoustically Transparent Duct technology has been built and tested on a centrifugal fan testbench at the Karlsruhe Institute of Technology. Measurements have been carried out on the test setup using a planar phased microphone array as well as a radial phased microphone array by colleagues from the Budapest University of Technology and Economics. The data has been processed using the ROSI beamforming method and the Segmented ROSI beamforming method. The investigation presents sample data for each approach and discusses the advantages and disadvantages of each. It is shown that the beamforming investigation of a centrifugal test bench can successfully be carried utilizing this technology, with each approach having its advantages and disadvantages. LA - English DB - MTMT ER - TY - CONF AU - Hincz, Krisztián AU - Pool Blanco, Sherly Joanna AU - Rosa, Richárd Joao AU - Koren, Márton AU - Balczó, Márton ED - Block, P. ED - Boller, G. ED - De Wolf, C. ED - Pauli, J. ED - Kaufmann, W. TI - Wind load analysis of a series of arch-supported membrane structures T2 - Proceedings of IASS Annual Symposia 2024 PB - International Association for Shell and Spatial Structures (IASS) PY - 2024 PG - 10 UR - https://m2.mtmt.hu/api/publication/34913564 ID - 34913564 LA - English DB - MTMT ER - TY - JOUR AU - Papp, Bálint AU - Istók, Balázs AU - Koren, Márton AU - Balczó, Márton AU - Kristóf, Gergely TI - Statistical assessment of the concentration fluctuations in street canyons via time-resolved wind tunnel experiments JF - JOURNAL OF WIND ENGINEERING AND INDUSTRIAL AERODYNAMICS J2 - J WIND ENG IND AEROD VL - 246 PY - 2024 PG - 17 SN - 0167-6105 DO - 10.1016/j.jweia.2024.105665 UR - https://m2.mtmt.hu/api/publication/34742505 ID - 34742505 N1 - Export Date: 18 March 2024 Correspondence Address: Papp, B.; Department of Fluid Mechanics, Műegyetem rkp. 3, Hungary; email: papp.balint@gpk.bme.hu Funding details: European Commission, EC, VEKOP-2.3.3-15-2017-00017 Funding details: Gedeon Richter, PD 127919 Funding details: Richter Gedeon Talentum Alapítvány Funding details: Nemzeti Kutatási, Fejlesztési és Innovaciós Alap, NKFIA Funding details: Innovációs és Technológiai Minisztérium, ÚNKP-21-3-I-BME-252 Funding details: National Research, Development and Innovation Office, TKP-6-6 Funding text 1: The present study was funded by grant no. K 124439 from the National Research, Development, and Innovation Office, Hungary. Project no. TKP-6-6/PALY-2021 has been implemented with the support provided by the Ministry of Culture and Innovation of Hungary from the National Research, Development and Innovation Fund, financed under the TKP2021-NVA funding scheme. Bálint Papp's contribution to this paper was supported by the ÚNKP-21-3 New National Excellence Program of the Ministry for Innovation and Technology (Grant No. ÚNKP-21-3-I-BME-252), as well as by the Gedeon Richter Talent Foundation (registered office: Gyömrői út 19–21, 1103 Budapest, Hungary), established by Gedeon Richter Plc. within the framework of the Gedeon Richter PhD Scholarship. Márton Balczó gratefully acknowledges the support of project PD 127919 of the National Research, Development, and Innovation (NRDI) Fund, entitled “Application and validation of measurement techniques related to the physical modeling of the atmospheric boundary layer in a new boundary layer wind tunnel”. The authors wish to acknowledge the support of the European Union and of the Hungarian Government in the project VEKOP-2.3.3-15-2017-00017 "Establishment of a Laboratory for Atmospheric Flows". Funding text 2: The present study was funded by grant no. K 124439 from the National Research, Development, and Innovation Office, Hungary . Project no. TKP-6-6/PALY-202 1 has been implemented with the support provided by the Ministry of Culture and Innovation of Hungary from the National Research, Development and Innovation Fund, financed under the TKP2021-NVA funding scheme. Bálint Papp's contribution to this paper was supported by the ÚNKP-21-3 New National Excellence Program of the Ministry for Innovation and Technology (Grant No. ÚNKP-21-3-I-BME-252 ), as well as by the Gedeon Richter Talent Foundation (registered office: Gyömrői út 19–21, 1103 Budapest, Hungary), established by Gedeon Richter Plc., within the framework of the Gedeon Richter PhD Scholarship. Márton Balczó gratefully acknowledges the support of project PD 127919 of the National Research, Development, and Innovation (NRDI) Fund , entitled “Application and validation of measurement techniques related to the physical modeling of the atmospheric boundary layer in a new boundary layer wind tunnel”. The authors wish to acknowledge the support of the European Union and of the Hungarian Government in the project VEKOP-2.3.3-15-2017-00017 "Establishment of a Laboratory for Atmospheric Flows". AB - Time-resolved wind tunnel experiments are performed for three periodic street canyon configurations: one of uniform (H/W = 1) and two of variable building height (consisting of 0.5H and 1.5H tall towers in aligned and staggered arrangements) for perpendicular wind direction. The velocity field is mapped using Laser Doppler Anemometry (LDA), and the tracer gas concentration is sampled using Fast Flame Ionization Detection (FFID). The concentration field is characterized by the mean concentration and the characteristic percentiles of the concentration-time series, such as the median and the peak, represented by the 99th percentile, in a total of 1138 sampling points. The probability distribution of the concentration in each point is modeled using the gamma distribution, which is fitted based on the mean and the variance of the measured time series. The results show that the mean pedestrian exposure to air pollutants is significantly lower in the case of heterogeneous roof height, although the mean concentration at the leeward corner of the source canyon can locally exceed those of the uniform street canyons for both tower arrangements of variable building height. Moreover, it is shown that the concentration peaks for both tower configurations can significantly exceed those of the uniform canyons case, especially near the sources. © 2024 The Authors LA - English DB - MTMT ER - TY - JOUR AU - Shahzad, Hasan AU - Wang, Xinhua AU - Rasool, Ghulam AU - Lelkes, János AU - Majeed, Afraz Hussain AU - Li, Zhiyong AU - Raizah, Zehba TI - Entropy generation and advanced hydrothermal examination of ferrofluid confined within an irregular cavity under Lorentz forces JF - JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS J2 - J MAGN MAGN MATER VL - 593 PY - 2024 PG - 12 SN - 0304-8853 DO - 10.1016/j.jmmm.2024.171814 UR - https://m2.mtmt.hu/api/publication/34682341 ID - 34682341 N1 - Faculty of Energy and Power Engineering, School of Chemical Engineering and Energy Technology, Dongguan University of Technology, China College of Mechanical and Energy Engineering, Beijing University of Technology, China Department of Mechanical Engineering, Lebanese American University, Beirut, Lebanon Department of Fluid Mechanics, Faculty of Mechanical Engineering, Budapest University of Technology and Economics, Budapest, Hungary Department of Mathematics, Air University, PAF Complex E-9, Islamabad, 44000, Pakistan Department of Mathematics, College of Science, Abha, King Khalid University, Saudi Arabia Export Date: 4 March 2024 CODEN: JMMMD Correspondence Address: Wang, X.; College of Mechanical and Energy Engineering, China; email: sunxhking@aliyun.com Funding details: National Natural Science Foundation of China, NSFC, 12202102 Funding text 1: This research was supported by National Natural Science Foundation of China (Grant No.12202102), The authors are grateful to the support from Guangdong Provincial key Laboratory of Distributed Energy Systems. LA - English DB - MTMT ER -