Recent Advances in Urban Ventilation Assessment and Flow Modelling

0508559 - ÚT 2020 RIV CH eng M - Část monografie knihy
Kellnerová, Radka - Fuka, V. - Uruba, Václav - Jurčáková, Klára - Nosek, Štěpán - Chaloupecká, Hana - Jaňour, Zbyněk
On Street-Canyon Flow Dynamics: Advanced Validation of LES by Time-Resolved PIV.
Recent Advances in Urban Ventilation Assessment and Flow Modelling. Basel: MDPI Books, 2019 - (Buccolieri, R.; Hang, J.), s. 198-224, č. článku 161. ISBN 978-3-03897-807-7
Grant CEP: GA ČR(CZ) GA15-18964S
Institucionální podpora: RVO:61388998
Klíčová slova: wind tunnel * LES * validation * street canyon * coherent structures
Obor OECD: Meteorology and atmospheric sciences
https://www.mdpi.com/books/pdfdownload/book/1264

The advanced statistical techniques for qualitative and quantitative validation of Large Eddy Simulation (LES) of turbulent flow within and above a two-dimensional street canyon are presented. Time-resolved data from 3D LES are compared with those obtained from time-resolved 2D Particle Image Velocimetry (PIV) measurements. We have extended a standard validation approach based solely on time-mean statistics by a novel approach based on analyses of the intermittent flow dynamics. While the standard Hit rate validation metric indicates not so good agreement between compared values of both the streamwise and vertical velocity within the canyon canopy, the Fourier, quadrant and Proper Orthogonal Decomposition (POD) analyses demonstrate very good LES prediction of highly energetic and characteristic features in the flow. Using the quadrant analysis, we demonstrated similarity between the model and the experiment with respect to the typical shape of intensive sweep and ejection events and their frequency of appearance. These findings indicate that although the mean values predicted by the LES do not meet the criteria of all the standard validation metrics, the dominant coherent structures are simulated well.
Trvalý link: http://hdl.handle.net/11104/0304533