Comparison of RANSE and LES for Wind Structural Interaction

Abstract

Popularity of tall buildings increases due to technological advances, but Code-based designs are conservative and not reliable for structures beyond 200 m height. Conducting a wind tunnel test is expensive and the resources are limited. Hence, numerical modelling is an alternative where Reynolds Average Navier Stokes Equation (RANSE) and Large Eddy Simulation (LES) are such numerical techniques.In recent Computational Fluid Dynamic (CFD) studies, it could be observed that results have considerable deviations in flow separating and high turbulent areas. Hence a structured mesh was used here to perform mesh refinement in such critical locations to refine only the required areas.The objective of this study is to compare the RANSE and LES in interpreting the wind structural interactions using a structured mesh arrangement. This study will be limited to tall buildings of height less than 200m, rectangular in shape. Hence Commonwealth Advisory Aeronautical Council (CAARC) standard building model was used as the subject and Simulation results will then be compared with the values of the wind tunnel test available in the literature.It could be observed that the results obtained by RANSE simulation for a structured mesh has a deviation less than 10%. But natural variations of the wind are more clearly indicated with LES with a deviation even less than 3% in turbulent regions.