An improved consistent inflow turbulence generator for LES evaluation of wind effects on buildings

Abstract

This paper proposes an improved consistent inflow turbulence generator for reproducing spatially correlated turbulence fields with specified wind profiles and spectra for large eddy simulation (LES). The inflow turbulence is developed based on the widely used Random Flow Generation (RFG) technique, and improvements include obtaining more consistent wind spectra, direct control of spatial integral length scales, mitigation of fictitious pressure fluctuations caused by nonsatisfaction of divergence-free conditions, and iteration-based adaption of velocity profiles within the future building area. These improvements are obtained from strictly theoretical derivation, and the correctness of the proposed algorithm is verified by comparing the velocity profiles and the wind spectra of the simulated turbulence atmospheric boundary layer (ABL) with target values. The proposed turbulence generator is adopted to generate inflow turbulence for analyzing wind-induced pressure distributions on isolated low-rise buildings immersed in the turbulent ABL, and the comparison between simulated results and wind tunnel experimental results obtained by Tokyo Polytechnic University (TPU) is presented. Good agreement between the numerical and experimental results verifies the applicability of the proposed generator technique to LES of wind effects on low-rise buildings.