STUDY OF INFLOW TURBULENCE GENERATION METHODS WITH LARGE EDDY SIMULATION FOR ATMOSPHERIC BOUNDARY LAYER

The generation of inflow turbulence with prescribed atmospheric boundary layer (ABL) flow characteristics is one of the key issues for the accurate evaluation of wind effects on structures using large-eddy simulation (LES). The main objective of this paper is to validate and discuss the rationality and feasibility of different inflow turbulence generation methods for ABL flows with LES. The CDRFG (Consistent Discretizing Random Flow Generation) method and passive simulation method are used to generate the ABL flows, and the comparative analysis is carried out from the aspects of statistical characteristics, flow field structures and computational efficiency. Based on the numerical simulation results under different mesh systems, the meshing scheme of LES for wind effects on engineering structures is proposed. The results show that the flow field structures generated by the passive simulation method is more reasonable than that of CDRFG method, but the spatial coherency of turbulent flow field cannot be taken into consideration in advance. It also requires large computational costs and prior knowledge of flow field. The grid resolution of computational domain is of great importance for the accurate simulation of statistical characteristics and ABL flows structures. However, the grid resolution in the neighboring region around target buildings should be chosen according to the dominant frequency band for the wind-induced responses of engineering structures.