Verification of a CFD solver in near ground effect for aerodynamic behavior of airfoil NACA 0015

Numerical investigation was performed on NACA 0015 which is a symmetric airfoil. Pressure distribution and then lift and drag forces are verified. Changing of ground clearance was a considerable point. Also the angle of attack was changed from 0° to 10°. Pressure coefficient reaches its higher amounts on the wing lower surface when the ground clearance diminishes. Increment of the angle of attack leads to outspread of the high pressure domain over the lower surface and so leads to greater lift force. For higher angles of attack the ground clearance had no effect on the pressure distribution. Mostly for high angles of attack, the suction effect on the upper surface makes an adverse pressure gradient which can cause turbulent behavior and finally enhance drag force. To solve the problem SIMPLE algorithm is utilized. Moreover, QUICK algorithm and second-order upwind are used for momentum verification and turbulent viscosity, respectively. After all, the efficiency of the utilized model is checked. It is observed that k-e model cannot give acceptable results admitting experimental achievements in comparison with Spalart-Allmaras. This is depicted for drag and lift coefficient and also the pressure distribution on both surfaces of the airfoil.