Numerical study on effect of the turbulence initial conditions on transition flow over 2D airfoil.

The performance of the airfoil is strongly dependent on the development of the boundary layer on the surface and therefore an accurate prediction of the laminar to turbulent transition onset is essential. A grid independence study is performed, turbulence variables values have been changed frequently, regularly, and carefully so that they cover the entire range of acceptable values reported by previous researches. Effects of turbulent variating at far stream on turbulent boundary layer structure and on transition stage characteristics at moderate Reynolds number  have been studied over a full range of angles of attack of NACA0012. numerical results have been post-processed, analyzed and found that far stream turbulence variables have a significant effect on transition characteristic, their effects on skin friction is limited to small extent along wing surface where transition take place, increasing turbulence intensity or eddy viscosity ratio at far boundary shifts transition onset towards leading edge and increase transition length.