Numerical Simulation of 3D Subsonic External Flow in the Stalled Region

Predicting the aerodynamic forces on the airfoil in the stalled region accurately using Computational Fluid Dynamics method is a critical task due to the strong vortex dynamics involved. Research publications (Ref.01 David Hartwanger et.al and Ref.2 Frank Bertagnolio et.al) explain the need of advanced turbulence models for accurately predicting the flows in the stalled region. Other research publications have elaborated the disadvantages of 2 D CFD simulations with reference to accuracy of the analysis results in the stalled region compared with the experimental data. (Ref. 3 H.Gao et.al and Ref. 04 S.Sarada, M.Shiva Shankar and Rudresh).These literatures reiterated the need of 3D CFD simulations to accurately capture the lift and drag coefficients in the stalled region. The objective of this work is to conduct 3D Incompressible, steady state ,Viscous Navier-Stokes simulations for NACA 64618 subsonic airfoil using ANSYS FLUENT Computational Fluid Dynamics Software. Analysis will be conducted for three different important turbulence models namely K-epsilon turbulence model with standard wall functions, Spalart allmaras turbulence model and K-omega shear stress turbulence model .Each of the turbulence model mentioned will employ different technique in modelling the boundary layer. This study will analyze all the merits and demerits of these three turbulence model with respect to accuracy of the CFD analysis solution, stability of the solution focusing mainly in the stalled region. CFD simulations will be carried out at free stream Reynolds number of 3 million and CFD analysis results will be compared with wind tunnel test data.