The Improvement Of Inlet Turbulence Boundary Condition In CWE And Detached Eddy Simulation

With the development of numerical simulation in the field of wind engineering, the accuracy of Computational Wind Engineering (CWE) attracts more and more attention. This thesis has carried on the research of the atmosphere boundary condition simulation, and has investigated the effects of different inflow boundary conditions on the results of flow field around the bluff body calculated by the method of numerical simulation. Finally, this text has introduced Detached Eddy Simulation, which is a new method of unsteady numerical simulation in Computational Fluid Dynamic (CFD) field. It's feasible that taking unsteady numerical simulation with DES to calculate the flow field around the bluff body.The research work of this thesis is mainly focused on the following aspects:1. How to give the proper inflow boundary conditions of the atmosphere boundary layer can obtain proper mean wind profile and turbulence kinetic energy profile inside the numerical wind-tunnel, is an important problem in numerical simulation. For SST k-ωModel, the problem has been solved from the aspects of turbulence kinetic energy approximate expression and eddy viscosity. It's the foundation of researching the inflow boundary condition influence on the accuracy.2. The comparison of the full scale data and the results of flow around a 6m cubic model and a Silsoe model with various inflow conditions are taken in this text. It could improve the numerical simulation accuracy that setting the proper inflow boundary expression and turbulence model parameters for SST model. The results of the separated regions are sensitive to inflow turbulence kinetic energy.3. Detached Eddy Simulation combines the advantages of Reynolds Averaged Navier-Stokes (RANS) model and Large Eddy Simulation (LES). It is a high effectual unsteady simulation method. DES overcomes the difficultness of solving boundary condition in LES, so it saves a lot of computing resources. The text compares DES and RANS calculations of vortex-shedding flow past a square cylinder at Re=22000. The DES calculations could capture the small scale vortexes and agree with the experimental data very well. It's a basic and important task for further research of DES.