STALL SIMULATION OF FLOW AROUND AN AIRFOIL USING LES MODEL AND COMPARISON OF RANS MODELS AT LOW ANGLES OF ATTACK

In this paper, the influence of turbulence modeling, Reynolds number and stall conditionon the fluid numerical solution over NACA0012 airfoil is studied by using the OpenFOAMpackage. Large-eddy simulation (LES) turbulence model is used to simulate flow at a highangle of attack in near-stall or stall condition. Some vortexes are formed and caused toappear a fluctuation behavior of pressure distribution on the upper surface of the airfoil.Three RANS turbulence models, i.e., K-ω SST, K-ε and RNG K-ε are used at low angles ofattack than stall condition and lift/drag coefficients of them are compared. Among differentturbulence models, the best result for lift coefficient is obtained once K-w SST turbulencemodel is used and the best drag coefficient is obtained by RNG K-ε turbulence model. K-ω SST turbulence model predicted the beginning of stall condition accurately whereas twoother models were not able to predict it. The effects of Reynolds number on the lift coefficienthave been investigated. It is observed that by increasing Reynolds number at constant Machnumber the lift coefficient is increased and stall phenomena is happened at a higher angle ofattack.