Abstract

A self-adaptive upwinding method for large eddy simulation is proposed to reduce the numerical dissipation of a low-order numerical scheme on unstructured elements. This method is used to extend an existing Reynolds-averaged Navier-Stokes code to a large eddy simulation code by adjusting the contribution of the upwinding term to the convective flux. This adjustment is essentially controlled by the intensity of the local wiggle and reduces the upwind contribution in the Roe-MUSCL scheme. First, the stability characteristic of the new scheme is studied using a channel flow stability test. It is essential to ensure that the proposed scheme is able to adjust upwinding in the presence of very high gradients and that it prohibits the divergence of the simulation. Second, the decaying isotropic turbulence is simulated to study the capability of the new scheme to generate the suitable decaying rate for the total kinetic energy and its influence over the slope of the energy spectrum at different computational times. Finally, the flow separation phenomenon over a NACA0025 profile is numerically investigated and results are compared with experimental data.