CFD analysis of cross-ventilation flow in a group of generic buildings: Comparison between steady RANS, LES and wind tun
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CFD analysis of cross-ventilation flow in a group of generic buildings: Comparison between steady RANS, LES and wind tunnel experiments Research Article
Mohammadreza Shirzadi1 (), Parham A. Mirzaei2,Yoshihide Tominaga1 1. Wind and Fluid Engineering Research Center, Niigata Institute of Technology, Kashiwazaki, Japan 2. Architecture and Built Environment Department, University of Nottingham, Nottingham, UK
Abstract
Keywords
Computational fluid dynamics (CFD) results generated by the steady Reynolds-averaged NavierStokes equations (SRANS) model and large eddy simulation (LES) are compared with wind tunnel experiments for investigating a cross-ventilation flow in a group of generic buildings. The mean flow structure and turbulence statistics are compared for SRANS based on different two-equation turbulence models with LES based on the Smagorinsky subgrid-scale turbulence model. The LES results show very close agreement with the experimental results in the prediction of the timeaveraged velocity, wind surface pressure around and inside the building, and crossing flow through the openings. In contrast, SRANS fails to predict the most important features of cross-ventilation. LES reproduces well the anisotropic turbulence property around and inside the cross-ventilated building, which is closely related to the transient momentum transfer caused in street canyon flows and has a significant influence on the mean flow structure. In contrast, SRANS could not inherently reproduce such transient fluctuations and anisotropic turbulence property, which results in low accurate predictions for the time-averaged velocity components, wind surface pressure distribution and crossing airflow rate up to 100% error.
CFD,
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Introduction
E-mail: [email protected]
LES, wind tunnel experiment, cross-ventilation, sheltered building
Article History Received: 14 February 2020 Revised: 16 April 2020 Accepted: 28 April 2020 © Tsinghua University Press and Springer-Verlag GmbH Germany, part of Springer Nature 2020
2020b; Bazdidi-Tehrani et al. 2019; Kosutova et al. 2019). Analyses of cross-ventilation flow over simplified isolated buildings have been studied extensively during the past thirty years (Kato et al. 1992; Straw et al. 2000; Jiang and Chen 2003; Ohba et al. 2004; Kobayashi et al. 2009, 2010; Ramponi and Blocken 2012b; Etheridge 2015). The complex mechanism of cross-ventilation in mean flow structure as well as highly transient nature for an unsheltered cuboid building are discussed using extensive wind tunnel experiments by Tominaga and Blocken (2016). On this basis, the presence of flapping jet and kelvin-Helmholtz instability around the windward jet was clearly shown using a special flow visualization technique (Tominaga and Blocken 2016; Shirzadi et al. 2020b). Furthermore, application of CFD models, based on steady Reynolds-averaged Navier-Stokes equations (SRANS) model (Kurabuchi et al. 2000; Straw et a. 2000; Hu et al. 2005; Kobayashi et al. 2010; Nikas et al. 2010; Perén et al. 2015b; Shirzadi et al. 2018a, b) and la
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