@article{MTMT:34742505,
	title = {Statistical assessment of the concentration fluctuations in street canyons via time-resolved wind tunnel experiments},
	url = {https://m2.mtmt.hu/api/publication/34742505},
	author = {Papp, Bálint and Istók, Balázs and Koren, Márton and Balczó, Márton and Kristóf, Gergely},
	doi = {10.1016/j.jweia.2024.105665},
	journal-iso = {J WIND ENG IND AEROD},
	journal = {JOURNAL OF WIND ENGINEERING AND INDUSTRIAL AERODYNAMICS},
	volume = {246},
	unique-id = {34742505},
	issn = {0167-6105},
	abstract = {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},
	keywords = {Probability distributions; Time series; Classifiers; Gamma distribution; Gamma distribution; Air quality; Doppler effect; Anemometers; Roofs; CONCENTRATION FLUCTUATIONS; Wind tunnels; Urban air quality; Urban air quality; Non-uniform; Wind tunnel measurements; street canyon; street canyon; concentration fluctuation; Laser doppler anemometry; Laser Doppler velocimeters; flame ionization detection; Peak concentrations; Peak concentrations; Building height; Fast Flame Ionization Detection (FFID); Laser Doppler Anemometry (LDA); Non-uniform building height; Variable roof height; Wind tunnel measurement; Fast flame ionization detection; Laser dopple anemometry; Non-uniform building height; Variable roof height},
	year = {2024},
	eissn = {1872-8197},
	orcid-numbers = {Papp, Bálint/0000-0001-8043-5271; Istók, Balázs/0000-0002-0248-0074; Balczó, Márton/0000-0002-1273-3047; Kristóf, Gergely/0000-0001-7572-6875}
}

@article{MTMT:34682341,
	title = {Entropy generation and advanced hydrothermal examination of ferrofluid confined within an irregular cavity under Lorentz forces},
	url = {https://m2.mtmt.hu/api/publication/34682341},
	author = {Shahzad, Hasan and Wang, Xinhua and Rasool, Ghulam and Lelkes, János and Majeed, Afraz Hussain and Li, Zhiyong and Raizah, Zehba},
	doi = {10.1016/j.jmmm.2024.171814},
	journal-iso = {J MAGN MAGN MATER},
	journal = {JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS},
	volume = {593},
	unique-id = {34682341},
	issn = {0304-8853},
	year = {2024},
	eissn = {1873-4766},
	orcid-numbers = {Rasool, Ghulam/0000-0002-5880-9553; Lelkes, János/0000-0002-6205-4923}
}

@article{MTMT:34562518,
	title = {Vibrations and energy distribution in inhomogeneous rods with elastic and viscous boundary conditions},
	url = {https://m2.mtmt.hu/api/publication/34562518},
	author = {Lelkes, János and Bak, Bendegúz Dezső and Kalmár-Nagy, Tamás},
	doi = {10.1038/s41598-024-52860-4},
	journal-iso = {SCI REP},
	journal = {SCIENTIFIC REPORTS},
	volume = {14},
	unique-id = {34562518},
	issn = {2045-2322},
	abstract = {Functionally graded materials have broad engineering applications including mechanical engineering, electronics, chemistry, and biomedical engineering. One notable advantage of such materials is that their stiffness distribution can be optimized to avoid stress concentration. A novel approach for solving the equations describing the longitudinal vibration of functionally graded rods with viscous and elastic boundary conditions is proposed. The characteristic equation of the system is derived for the solution of the undamped case for the constant stiffness rod. Then, a homotopy method is applied to compute the eigenvalues and mode shapes of graded rods for viscoelastic boundary conditions. The changes of the eigenvalues and mode shapes as function of the damping parameters are investigated. The optimal damping of the system is computed. It is shown that the qualitative behavior depends on the relation between the actual damping and the optimal damping of the system. The energy density distribution of graded rods is also discussed. An energy measure, the mean scaled energy density distribution is introduced to characterize the energy distribution along the rod in the asymptotic time limit. The significance of such a measure is that it reveals how the energy tends to distribute along the rod. It is shown that the energy distribution can be manipulated by changing the damping parameters. Qualitative changes depending on the relation between the actual damping and the optimal damping are highlighted.},
	year = {2024},
	eissn = {2045-2322},
	orcid-numbers = {Lelkes, János/0000-0002-6205-4923; Bak, Bendegúz Dezső/0000-0003-1378-875X; Kalmár-Nagy, Tamás/0000-0003-1374-2620}
}

@article{MTMT:34518784,
	title = {Further development of rotating beamforming techniques using asynchronous measurements},
	url = {https://m2.mtmt.hu/api/publication/34518784},
	author = {Kocsis, Bálint and Horváth, Csaba},
	doi = {10.1142/S2591728523400066},
	journal-iso = {J THEOR COMPUT ACOUS},
	journal = {Journal of Theoretical and Computational Acoustics},
	volume = {32},
	unique-id = {34518784},
	issn = {2591-7285},
	abstract = {When rotating noise sources, such as turbomachinery, are investigated using phased microphone array measurements and beamforming, sidelobes appear on the resulting beamforming maps. Sidelobes can be decreased by increasing the number of microphones. However, if the investigated phenomenon is steady, then there is a cost-effective alternative: performing asynchronous measurements using phased arrays having a limited number of microphones. The single beamforming maps can be combined in order to arrive at results that are superior in resolution and sidelobe levels. This technique has been investigated in the literature, but according to the authors’ best knowledge, has not yet been applied to turbomachinery. This article introduces a means for applying the asynchronous measurement technique and the combination methods for rotating noise sources. The combination methods are demonstrated on two rotating point sources (both in simulations and measurements), and then on an axial flow fan test case. In the case of the two rotating point sources, the achievable improvement in resolution, average-, and maximum sidelobe levels are shown as compared to the single results. In the case of the axial flow fan, it is demonstrated that the combination methods provide more reliable noise source locations and reveal further noise sources.},
	year = {2024},
	eissn = {2591-7811},
	orcid-numbers = {Horváth, Csaba/0000-0002-5154-9760}
}

@article{MTMT:34495646,
	title = {Predicting Concentration Fluctuations of Locally Emitted Air Pollutants in Urban-like Geometry Using Deep Learning},
	url = {https://m2.mtmt.hu/api/publication/34495646},
	author = {Papp, Bálint and Kristóf, Gergely},
	doi = {10.3311/PPme.23391},
	journal-iso = {PERIOD POLYTECH MECH ENG},
	journal = {PERIODICA POLYTECHNICA-MECHANICAL ENGINEERING},
	volume = {68},
	unique-id = {34495646},
	issn = {0324-6051},
	abstract = {The accurate quantification of concentration fluctuations is crucial when evaluating the exposure to toxic, infectious, reactive, flammable, or explosive substances, as well as for the estimation of odor nuisance. However, in the field of Computational Fluid Dynamics (CFD), the industry currently relies predominantly on steady-state RANS turbulence models for simulating near-field pollutant dispersion, which are only capable of producing the time-averaged concentration field. This paper presents a regression relationship for calculating the standard deviation of the local concentration based on the mean concentration and the downstream distance from a point source, over a city-like surface, in the case of the wind direction perpendicular to the streets. The desired peak values and other statistical characteristics can be predicted by assuming a gamma distribution which is fitted based on the average and standard deviation. To obtain the regression function, a deep neural network model was used. The model was trained using time-resolved concentration data obtained from wind tunnel experiments. The validation results show that the concentration fluctuations predicted by the DNN-based model are in satisfactory agreement with the measurement data in terms of the skewness, the kurtosis, the median, and the peak concentrations. Furthermore, the present paper suggests a workflow for estimating the concentration fluctuations based on RANS CFD results, as well as recommendations for generating further training data for specific applications.},
	keywords = {simulation; Environment; dispersion; fluid dynamics; CFD; Urban air quality},
	year = {2024},
	eissn = {1587-379X},
	pages = {44-52},
	orcid-numbers = {Papp, Bálint/0000-0001-8043-5271; Kristóf, Gergely/0000-0001-7572-6875}
}

@misc{MTMT:34518816,
	title = {International Journal of Turbomachinery, Propulsion and Power. Selected Turbomachinery Papers from the 18th Conference on Modelling Fluid Flow CMFF'22},
	url = {https://m2.mtmt.hu/api/publication/34518816},
	editor = {Vad, János and Horváth, Csaba and Benedek, Tamás},
	unique-id = {34518816},
	year = {2023},
	orcid-numbers = {Vad, János/0000-0001-5589-1603; Horváth, Csaba/0000-0002-5154-9760; Benedek, Tamás/0000-0001-8057-3156}
}

@inproceedings{MTMT:34499886,
	title = {Mezoskálás hatások szerepe az áramlási térre és a terjedésre explicit érdességi rétegben},
	url = {https://m2.mtmt.hu/api/publication/34499886},
	author = {Koren, Márton and Kristóf, Gergely},
	booktitle = {XXVI. Tavaszi Szél Konferencia 2023},
	unique-id = {34499886},
	year = {2023},
	pages = {501-519},
	orcid-numbers = {Kristóf, Gergely/0000-0001-7572-6875}
}

@inproceedings{MTMT:34496635,
	title = {‪Semi-Empirical Method to Approximate the Poincaré-Lyapunov Constant for the Delayed-Liénard Equation‬},
	url = {https://m2.mtmt.hu/api/publication/34496635},
	author = {Horváth, Dávid András and Kalmár-Nagy, Tamás},
	booktitle = {Book of Abstracts from 9th International Scientific Conference on Advances in Mechanical Engineering},
	unique-id = {34496635},
	year = {2023},
	pages = {39},
	orcid-numbers = {Kalmár-Nagy, Tamás/0000-0003-1374-2620}
}

@article{MTMT:34299741,
	title = {Experimental and numerical investigation of the blade tip-related aeroacoustic sound source mechanisms of a ducted low-speed axial flow fan},
	url = {https://m2.mtmt.hu/api/publication/34299741},
	author = {Lendvai, Bálint and Benedek, Tamás},
	doi = {10.1016/j.apacoust.2023.109705},
	journal-iso = {APPL ACOUST},
	journal = {APPLIED ACOUSTICS},
	volume = {215},
	unique-id = {34299741},
	issn = {0003-682X},
	year = {2023},
	eissn = {1872-910X},
	orcid-numbers = {Lendvai, Bálint/0000-0003-3741-2001; Benedek, Tamás/0000-0001-8057-3156}
}

@article{MTMT:34234013,
	title = {Parameter Identification of the Lagrangian-averaged Vorticity Deviation Vortex Detection Method Through the Investigation of Fluid Flow Around Solid Bodies},
	url = {https://m2.mtmt.hu/api/publication/34234013},
	author = {Kovács, Kinga Andrea and Balla, Esztella Éva},
	doi = {10.3311/PPme.22874},
	journal-iso = {PERIOD POLYTECH MECH ENG},
	journal = {PERIODICA POLYTECHNICA-MECHANICAL ENGINEERING},
	volume = {67},
	unique-id = {34234013},
	issn = {0324-6051},
	abstract = {The main focus of the current paper is the detection of vortices in fluid flow around a circular cylinder and a square cylinder, with an emphasis on the identification of the parameters used for vortex detection. The authors aim to enhance the practicality of an existing vortex detection method (Lagrangian-averaged vorticity deviation) by providing recommendations for the settings of the vortex detection parameters. The simulations were carried out using ANSYS Workbench 2022 R2, encompassing Reynolds numbers between 12 and 140, and angles of incidence from 0(degrees) to 45(degrees). The vortex detection was performed using MATLAB R2020b. The paper provides a comprehensive description of the parameters involved in the detection process and their significance, as well as the implementation of the parameter identification. The study results in the determination of the suggested parameter ranges, and a comparative analysis of different vortex detection methods is also presented for the case of the circular cylinder.},
	keywords = {parameter identification; aerodynamics; Circular cylinder; NUMERICAL-ANALYSIS; Vortex detection; bluff bodies},
	year = {2023},
	eissn = {1587-379X},
	pages = {293-302},
	orcid-numbers = {Balla, Esztella Éva/0000-0001-6617-4474}
}