用N-S方程求解柔壁翼型绕流

COMPUTATION OF FLEXIBLE-WALL AIRFOIL FLOW USING N-S EQUATIONS

用 N- S方程数值模拟带有自适应柔壁被动控制的翼型粘性绕流。用时间推进法求解这种准定常绕流。在时间历程中 ,柔壁自适应变化 ,最后与整个流场一起趋于定常。

The 2 D Reynolds averaged compressible unsteady full Navier Stokes equations are solved by using the Beam Warming scheme with Baldwin Lomax turbulent model about the flexible wall airfoil.A method is proposed which can treat the locally changing surface of airfoils.The adaptive surface in the shock region can influence the shock/boundary layer interaction.Comparison has been made between the flow fields over NACA0021 airfoil with and without the flexible wall.Since we use the time marching method to get the steady results,the main difficulty in the present case is the treatment of the flexible wall boundary which changes its shape as the solution proceeds.The deflections of the flexible wall as function of the pressure over it can be found by the mechanics of the material.We proposed a method of locally changing grids to avoid the global interpolation.The locally changed grids maintain the good quality of the original grids.The calculated results show that a strong shock splits into two weak shocks in comparison with the case without the control.