NUMERICAL INVESTIGATION OF FLOW TRANSITION FOR NACA-4412 AIRFOIL USING COMPUTATIONAL FLUID DYNAMICS

摘要

Numerical investigation of aerodynamics phenomena in the post stall region using Computational Fluid Dynamics is critical task due to the strong vortex dynamics involved. Literatures cited in this filed indicates that the Turbulence models employed in most of the commercial CFD software’s will assume the boundary layer around the airfoil as fully turbulent and hence the physical phenomena is wrongly addressed and also this approximation will lead to deviation in results from experimentally measured data in the post stall region. Research in this area concluded that the flow transition (boundary layer transition) from laminar to turbulent around the surface of the airfoil needs to be properly implemented in CFD analysis in order to have a reliable prediction in post stall region. This work aims in predicting the flow transition from laminar to turbulent for flow over NACA4412 airfoil in the incompressible flow regime.CFD analysis methodology involves the use of Mentors Shear Stress Transport Turbulence model(k-ω model)with transitional flow option.CFD analysis results are compared with wind tunnel test data.CFD analysis is also carried out with Spalart allmaras turbulence model which assumes the boundary layer as fully turbulent.