Large Eddy Simulation using One-Equation SGS Model based on Dynamic Procedure for Flows in Laminar-Transition Region
Keywords:LES, laminar-transition, non-equilibrium, one-equation dynamic model
Prediction of laminar-transition flows around an airfoil remain an issue in the large eddy simulation (LES) community. Hence, this paper aims to solve this issue by introducing a new dynamic one-equation kSGS model (OD). This model uses the advantage of the dynamic Smagorinsky procedure to represent the energy transfer between grid-scale (GS) and sub-grid-scale (SGS). This procedure is incorporated in order to calculate the coefficient in the production term of the turbulent kinetic energy, kSGS transport equation. The dynamic procedure implemented in this work does not require any averaging in homogeneous direction and this has given the OD model an extra advantage in terms of the applicability for engineering applications. The main feature of the OD model has been proven in identifying the non-turbulent region around the airfoil where the kSGS and eddy viscosity automatically turns to zero. In addition, the OD model also has the capability to capture the laminar region even though the grid used is considered coarse. As a result, we revealed that the artificial procedures to vanish the eddy viscosity in laminar region can be resolved by applying the OD model. Thus, the OD model is believed suitable for unsteady flow simulation such as dynamic stall where the transition point is changed with the variation of angleof-attack.