Large-Eddy Simulation Of The Turbulent Boundary Layer On A Plate

The basic idea of large eddy simulation (LES) is that instantaneous turbulent flow is filtered into large scale motion and small scale motion, and large scale is computed directly but small scale is simulated by subgrid scale model. When LES is applied into flow mechanism problem, such as the transition, turbulent boundary layer and so on, the numerical schemes and subgrid scale model is very important and rigor.The subgrid scale model is the key to large eddy simulation. This thesis adopted dynamic subgrid-scale model (DSM), the stress of the minimal resolved scale achieved by the test filter is analogous to the one of the subgrid scale, and DSM is obtained. DSM can response to the state of the flow. But this model is just two orders, in order to ensure availability of the model, the scheme should be high order and without dissipation.High-order WENO scheme can be applied to the complicated flow within the shock. This scheme can capture the shock and insist on high order in smooth region. But this WENO is too dissipative to the detailed simulation of turbulent flow, especially for large eddy simulation. The WENO scheme is developed into symmetry WENO scheme, called WENOSYM scheme. The dissipation of WENOSYM is theoretically zero. Through several simulations, the WENOSYM is less dissipative than WENO scheme, robust shock capturing and high order.The inlet condition is difficult to be given as the turbulent boundary layer is simulated. With a new inlet condition of turbulent boundary layer in the base of different fluctuation of the inner and outer layer, this thesis simulated the turbulent boundary layer in combination of WENOSYM scheme, dynamic subgrid-scale model by large eddy simulation. The result shows the flow didn't develop to turbulence. The numerical dissipation of above methods is still higher when simulating mechanism of turbulence.