NUMERICAL SIMULATION OF SUBSONIC TURBULENT FLOW OVER NACA0012 AIRFOIL: EVALUATION OF TURBULENCE MODELS

Subsonic turbulent flow over NACA0012 airfoil at the Reynolds number of 3×106 and different angles of attack (from -12º to 20º) is simulated using OpenFOAM. The flow is assumed ort steady and two-dimensional. Different turbulence models including Spalart-Allmaras, realizable k-ɛ and k-ω Shear Stress Transport (SST) are employed and their accuracy evaluated through the comparison ort h results with the available experimental data. The main focus has been put on the two regions around the airfoil, namely, the transition region and the turbulent region that are of high importance in the evaluation of computational fluid dynamics (CFD) codes. Hence, the laminar to turbulent transition point was determined at various Reynolds numbers in order to get accurate results ort he drag coefficient. It was found that by increasing the angle of attack, the accuracy of all the turbulence models used in the OpenFOAM software would reduce. In addition, the Spalart-Allmaras model showed highest accuracy compared with the other models tested in the present research. In fact, these turbulence models are unable to detect the point where the transition from laminar to turbulent flow occurs and thus have deficiency in determining the accurate flow quantities. Therefore, in both the theoretical and empirical studies the transition effects should be taken into account especially in critical analyses.

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