Three-dimensional large eddy simulation urban neighborhood model with updated building drag coefficient and universal multiscale Smagorinsky model

Abstract

Various drag-porosity models for urban buildings have been developed to explain the changes caused by building layout on airflow and turbulence in urban neighborhoods. One-dimensional building drag-porosity models with different model coefficients have been widely used to study the airflow in urban neighborhoods. However, these models often rely on length scales to calculate the eddy viscosity and dissipation rate using K-theory, which also need to be adjusted for different urban configurations. This study aims to address this limitation by developing a building drag parameterization version of the three-dimensional large eddy simulation neighborhood model (LES building drag-porosity model). The proposed model incorporates an updated building drag coefficient and the universal multiscale Smagorinsky model, making it suitable for simulating airflows in idealized and real urban neighborhoods with compact mid-rise buildings. To evaluate the performance of the proposed model, building-resolving LES was conducted for idealized and real neighborhoods. The vertical profiles of the turbulent kinetic energy and vertical turbulent momentum flux obtained using proposed model are superior to those obtained using previous models.