Study of wind flow over a 6 m cube using improved delayed detached Eddy simulation

The proper selection of a turbulent model greatly influences the prediction of wind in an urban environment. The purpose of this study is to evaluate the capabilities of the improved delayed detached eddy simulation (IDDES) model in a wind flow simulation. A cube (Silsoe cube, 6 m in dimension) with a normal wind direction under typical atmospheric conditions was simulated. Some computational parameters were thoroughly evaluated and analyzed, including the grid resolution, the discretization time step and the sampling time. The selected time-step (0.002 s) and sampling time (10 min) are the most economic and effective. The experimental results and large eddy simulation (LES) results were used to evaluate the performance of the IDDES model. The simulation results include the mean, maximum, minimum, and standard deviation of the pressure coefficients, and the reattachment length. The IDDES model shows results similar to those obtained using the LES model. The distributions of instantaneous velocity field and pressure field around the cube were also discussed, we concluded that the IDDES model is able to provide the acceptable prediction of the mean and unsteady features compared with full-scale experimental data around the Silsoe cube. Our study suggests that the IDDES model could be able to simulate the wind-structure interaction around a Silsoe cube. For the simulation of wind flow over an urban area, IDDES model could be potentially suitable but need to be further verified because of more complex nature flow than cube.