Large eddy simulation of low-Reynolds-number flow past the SD7003 airfoil with an improved high-precision IPDG method

At low-Reynolds-number, the performance of airfoil is known to be greatly affected by the formation and burst of a laminar separation bubble (LSB), which requires a more precise simulation of the delicate flow structures. A framework based on the interior penalty discontinuous Galerkin method and large eddy simulation approach was adopted in the present study. The performances of various subgrid models, including the Smagorinsky (SM) model, the dynamic Smagorinsky (DSM) model, the wall-adapting local-eddy-viscosity (WALE) model, and the VREMAN model, have been analyzed through flow simulations of the SD7003 airfoil at a Reynolds number of 60000. It turns out that the SM model fails to predict the emergence of LSB, even modified by the Van-Driest damping function. On the contrary, the best agreement is generally achieved by the WALE model in terms of flow separation, reattachment, and transition locations, together with the aerodynamic loads. Furthermore, the influence of numerical dissipation has also been discussed through the comparison of skin friction and resolved Reynolds stresses. As numerical dissipation decreases, the prediction accuracy of the WALE model degrades. Meanwhile, nonlinear variation could be observed from the performances of the DSM model, which could be attributed to the interaction between the numerical dissipation and the subgrid model.