Direct Numerical Simulation of Flow Transition in Compressible Boundary LayerAround Airfoils

摘要

The three dimensional development of flow transition in both subsonic andsupersonic Joukowsky airfoil boundary layers are studied by direct numerical simulation (DNS). The numerical simulation is performed by a spatial approach. A full compressible Navier Stokes system in curvilinear coordinates is employed so that we can simulate the transition around general geometric configurations. The numerical results agree very well with the linear stability theory (LST) at the linear growth stage for both primary and second modes in the flat plate boundary layers. The whole process of controlled flow transition induced by blowing/suction around airfoils is simulated by directly solving the N-S system with Reynolds number around one million. Some differences are found in comparison to the incompressible counterpart, and some new phenomena for the transition around airfoils are observed which at least qualitatively agree with physics.