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 - Papp, Bálint AU - Kristóf, Gergely TI - Predicting Concentration Fluctuations of Locally Emitted Air Pollutants in Urban-like Geometry Using Deep Learning JF - PERIODICA POLYTECHNICA-MECHANICAL ENGINEERING J2 - PERIOD POLYTECH MECH ENG VL - 68 PY - 2024 IS - 1 SP - 44 EP - 52 PG - 9 SN - 0324-6051 DO - 10.3311/PPme.23391 UR - https://m2.mtmt.hu/api/publication/34495646 ID - 34495646 N1 - Funding Agency and Grant Number: Ministry of Culture and Innovation of Hungary from the National Research, Development and Innovation Fund [TKP-6-6/PALY-2021, TKP2021-NVA]; New National Excellence Program of the Ministry for Culture and Innovation from the source of the National Research, Development and Innovation Fund [UNKP-22-3-II-BME-109]; Gedeon Richter Talent Foundation Funding text: 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. Balint Papp's contribution to this paper was supported by the UNKP-22-3-II-BME-109 New National Excellence Program of the Ministry for Culture and Innovation from the source of the National Research, Development and Innovation Fund; as well as by the Gedeon Richter Talent Foundation (registered office: Gyoemroi ut 19-21, 1103 Budapest, Hungary) , established by Gedeon Richter Plc., within the framework of the Gedeon Richter PhD Scholarship. AB - 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. LA - English DB - MTMT ER - TY - CHAP AU - Koren, Márton AU - Kristóf, Gergely ED - Molnár, Dániel ED - Molnár , Dóra TI - Mezoskálás hatások szerepe az áramlási térre és a terjedésre explicit érdességi rétegben T2 - XXVI. Tavaszi Szél Konferencia 2023 PB - Doktoranduszok Országos Szövetsége (DOSZ) CY - Budapest SN - 9786156457370 PY - 2023 SP - 501 EP - 519 PG - 19 UR - https://m2.mtmt.hu/api/publication/34499886 ID - 34499886 LA - Hungarian DB - MTMT ER - TY - JOUR AU - Koren, Márton AU - Kristóf, Gergely TI - Investigation of the accuracy of the transient wind forcing model applied for a shear-driven LES JF - JOURNAL OF WIND ENGINEERING AND INDUSTRIAL AERODYNAMICS J2 - J WIND ENG IND AEROD VL - 236 PY - 2023 PG - 14 SN - 0167-6105 DO - 10.1016/j.jweia.2023.105363 UR - https://m2.mtmt.hu/api/publication/33702898 ID - 33702898 N1 - Correspondence Address: Koren, M.; Department of Fluid Mechanics, Műegyetem rkp. 3, Hungary; email: koren.marton@gpk.bme.hu AB - We examine the effectiveness of the Transient Wind Forcing (TWF), previously validated with field and wind tunnel experiments, using LES in large-scale and small-scale cyclic domains. The small domain includes only a part of the atmospheric boundary-layer height, so the effect of wind shear is modeled near its upper boundary with the TWF coupling method. It is essentially a time-dependent volume source of momentum, which is controlled using velocity time series extracted from a point in the large domain. Surface roughness is explicitly modeled in both domains. The dispersion of atmospheric pollutants is investigated by the Lagrange method. The model error of TWF coupling is quantitatively evaluated in the case of atmospheric boundary layers with different Coriolis parameters, atmospheric stability, and surface roughness. The results of the small model driven by the TWF method showed good agreement with the reference results obtained from the large domain based on the average wind speed and turbulence profiles between and directly above the buildings, as well as the concentration of air pollutants emitted at ground level. For this, it was also necessary to consider the pressure gradient corresponding to the geostrophic wind and the effect of the Coriolis force in the small domain. LA - English DB - MTMT ER - TY - CHAP AU - Koren, Márton AU - Balogh, Miklós AU - Kristóf, Gergely ED - Jurčáková, Klára ED - Kellnerová, Radka TI - Transient Wind Forcing: a method for modelling wind shear in building-scale Large Eddy Simulations T2 - PHYSMOD 2022 - International Workshop on Physical Modeling of Flow and Dispersion Phenomena PB - Ústav termomechaniky AV ČR CY - Prága SN - 9788087012819 PY - 2022 SP - 111 EP - 111 PG - 1 UR - https://m2.mtmt.hu/api/publication/33120024 ID - 33120024 LA - English DB - MTMT ER - TY - CHAP AU - Papp, Bálint AU - Istók, Balázs AU - Koren, Márton AU - Balczó, Márton AU - Kristóf, Gergely ED - Jurčáková, Klára ED - Kellnerová, Radka TI - Statistical assessment of the ventilation of street canyons based on time-resolved wind tunnel experiments T2 - PHYSMOD 2022 - International Workshop on Physical Modeling of Flow and Dispersion Phenomena PB - Ústav termomechaniky AV ČR CY - Prága SN - 9788087012819 PY - 2022 SP - 143 EP - 155 PG - 12 UR - https://m2.mtmt.hu/api/publication/33113557 ID - 33113557 LA - English DB - MTMT ER - TY - CHAP AU - Papp, Bálint AU - Kristóf, Gergely ED - Vad, János TI - Building Patterns Favorable for Air Quality: A Parameter Study Using LES T2 - Proceedings of Conference on Modelling Fluid Flow (CMFF'22) PB - Budapest University of Technology and Economics, Department of Fluid Mechanics CY - Budapest SN - 9789634218814 PY - 2022 SP - 438 EP - 451 PG - 14 UR - https://m2.mtmt.hu/api/publication/33113416 ID - 33113416 LA - English DB - MTMT ER - TY - CHAP AU - Bak, Bendegúz Dezső AU - Rochlitz, Róbert Zoltán AU - Kalmár-Nagy, Tamás AU - Kristóf, Gergely ED - Vad, János TI - Mechanistic turbulence: Targeted energy transfer in a multi-degree-of-freedom nonlinear oscillator T2 - Proceedings of Conference on Modelling Fluid Flow (CMFF'22) PB - Budapest University of Technology and Economics, Department of Fluid Mechanics CY - Budapest SN - 9789634218814 PY - 2022 SP - 357 EP - 364 PG - 8 UR - https://m2.mtmt.hu/api/publication/33108564 ID - 33108564 LA - English DB - MTMT ER - TY - CONF AU - Papp, Bálint AU - Kristóf, Gergely TI - The role of thermal convection in the dispersion of traffic-induced air pollutants in the Urban environment T2 - 20th International Conference on Harmonisation within Atmospheric Dispersion Modelling for Regulatory Purposes PY - 2021 SP - 1 EP - 5 PG - 5 UR - https://m2.mtmt.hu/api/publication/32893885 ID - 32893885 LA - English DB - MTMT ER - TY - JOUR AU - Papp, Bálint AU - Kristóf, Gergely AU - Gromke, Christof TI - Application and assessment of a GPU-based LES method for predicting dynamic wind loads on buildings JF - JOURNAL OF WIND ENGINEERING AND INDUSTRIAL AERODYNAMICS J2 - J WIND ENG IND AEROD VL - 217 PY - 2021 PG - 14 SN - 0167-6105 DO - 10.1016/j.jweia.2021.104739 UR - https://m2.mtmt.hu/api/publication/32128267 ID - 32128267 N1 - Funding Agency and Grant Number: NKFIH from the National Research, Development, and Innovation Office, Hungary [124439]; National Research Development and Innovation Fund [BME-NCS, BME-IE-WAT]; Ministry for Innovation and Technology; New National Excellence Program of the Ministry for Innovation and Technology [UNKP-19-2]; Gedeon Richter Talent Foundation (Budapest, Hungary); Gedeon Richter Plc., within the framework of the Gedeon Richter PhD Scholarship; CFD Funding text: This study was funded by grant no. K 124439, NKFIH from the National Research, Development, and Innovation Office, Hungary. The research reported in this paper and carried out at the Budapest University of Technology and Economics has been supported by the Na-tional Research Development and Innovation Fund (TKP2020 National Challenges Subprogram, Grant No. BME-NCS and TKP2020 Institution Excellence Subprogram, Grant No. BME-IE-WAT) based on the charter of bolster issued by the National Research Development and Innovation Office under the auspices of the Ministry for Innovation and Technology. The Ostpartnerschaften program from the German Academic Exchange Service (DAAD) is acknowledged for helping to initiate the collaboration. Balint Papp's contribution to this paper was supported by the UNKP-19-2 New National Excellence Program of the Ministry for Innovation and Technology; and the Gedeon Richter Talent Foundation (registered office: Gyodmro?i ut 19-21, 1103 Budapest, Hungary) , established by Gedeon Richter Plc., within the framework of the Gedeon Richter PhD Scholarship. The authors acknowledge the support of CFD. HU Ltd. in providing access to the necessary hardware and software, as well as express their gratitude towards Dipankar Choudhury (Vice President, Research) and Justin Hendrickson (Director of Product Management) of ANSYS, Inc. for providing insight to the simulation methods applied in ANSYS Discovery Live. LA - English DB - MTMT ER -