1Department of Mechanical Engineering, Sahand university of Technology, Tabriz, Iran
2Center for CFD Studies on Heat Engines, Cavitational Flows and Petroleum Industries,Department of Mechanical Engineering, University of Tabriz, Tabriz, Iran
The importance of the external flows around the airfoils got serious when the airplanes with high velocity crashed due to passing the critical Mach number. Those events caused to become clear the significance of the effects of the Mach number on the drag and lift forces. In this paper, the modeling of two standard airfoils for different angles of attack and various Mach numbers are. The external flows around the airfoil are solved by two turbulence models which are Splalart-Alamaras and k-ε models. Both of the airfoils have been modeling for Mach numbers from 0.8 to 1.2 and angles of attacks of 0 and 4 degrees. The pressure and drag coefficients, pressure force for both top and bottom walls of the airfoils are calculated by using the Spalart-Almaras and k-ε models. The results show that, the drag coefficient increases intensively when the Mach number is equal to one, then for a determined Mach number, the drag coefficient is stable. The drag force and coefficient of two above turbulence models in different Mach numbers are investigated and the location of the shock wave phenomenon for the airfoils NACA m1 and NACA 0015 with different angle of attacks is studied.