Generation of inflow turbulence using the local differential quadrature method

Abstract

When performing unsteady time-dependent Computational Fluid Dynamics (CFD) calculation to investigate dynamic wind–structure interactions, turbulence whose mean and fluctuating velocity components satisfy the requirements of the Atmospheric Boundary Layer (ABL) of the specified terrain category must be imposed at the inlet of the computational domain at each time step. This paper proposes incorporation of the local Differential Quadrature Method (DQM) and the recycling technique to simulate inflow turbulence for wind engineering applications. Local DQM is utilized to help simulate the high-frequency component of turbulence because of its inherent high accuracy. The recycling technique is utilized to control the mean-velocity profile and boundary layer height. In this paper, local DQM is first described and verified by a numerical simulation of turbulence in a channel. It is then utilized in conjunction with the recycling technique to generate three kinds of turbulent boundary layers with different mean-velocity profiles. The results show that local DQM is a good approach to generation of inflow turbulence, particularly to increase the turbulence energy of high-frequency components.