Direct Numerical Simulations of Transitional and Turbulent Flow on a Turbine Airfoil

Abstract

A direct numerical simulation of transitional/turbulent flow on a low-speed turbine airfoil is presented here. The nonconservative form of the Navier–Stokes equations for compressible flows is used for this simulation. The numerical method used to solve these equations is a high-order-accurate upwind-biased iterative-implicit finitedifference scheme and is also presented here. The algorithm and the simulation are extensions of earlier efforts in direct simulations of transition and turbulence on flat plates. The present investigation has additional features, such as surface curvature, an adverse pressure gradient region on the airfoil, and trailing-edge vortex shedding. The results provided in the paper include the time-averaged pressure and the Stanton number distribution on the airfoil surface and turbulence statistics and flow visualization in the transitional/turbulent regions. Comparisons with experimental and computational data obtained for flows over flat plates and in channels are provided. The results indicate that the essential features of transition and turbulence have been captured.