PARALLEL DIRECT METHOD OF LES FOR TURBULENT WIND FIELD WITH HIGH REYNOLDS NUMBER

In the environmental fluid mechanics, the turbulent wind field in the atmospheric layer is the driving force and the foundation for the study of the natural environment characteristics such as the wind and sand flow and the wind and snow flow. The calculation simulation of the turbulent wind field is usually used the turbulent boundary layer model, where the large eddy simulation (LES) is an effective computational tool. The parallel computing technology is one of the key technologies for the LES simulation to solve the large-scale turbulent wind field with the high Reynolds number. In the LES simulation of the turbulent wind field, the parallel computing technique of the pressure Poisson equation is the difficult point for the scale parallel calculation. Based on the characteristics of the turbulent wind field flow simulation, the horizontal grids are equidistant spacing and the grids perpendicular to the ground are non-equidistant. Using the FFT decoupling three-dimensional Poisson equation to make it a one-dimensional three-dimensional diagonal equation, and the parallel-able PDD technology is used to solve the three-diagonal equation for solving the difficult problem of the pressure Poisson equation in the scale parallel calculation, and the three-dimensional pressure Poisson equation can be solved directly in parallel. Combined with the other parallel momentum equation calculations, the parallel direct method of LES (PDM-LES) for the turbulent wind field simulation is established. The new method is tested in parallel on the supercomputer, and the parallel computing efficiency is 90\%. The new method can be used for the large-scale parallel calculation for LES simulation of the turbulent wind field. The results show that there is a striped pre-order structure near the wall in the transient velocity distribution. The velocity distribution of the average field conforms to the logarithmic law, and the turbulence characteristic of the wind field is basically reasonable.