Numerical calculations of high lift flow using structured and unstructured methods

Abstract

At the DLR Institute for Design Aerodynamics current research in the area of high lift aerodynamics is directed towards the development of a computational analysis capability for high lift systems. The Navier-Stokes equations are solved with a multigrid method based on central spatial differencing and Runge-Kutta time stepping. Two particular problems are addressed in this paper. The first concerns the calculation of maximum lift or a single airfoil and a clean wing configuration. The accuracy of the basic structured flow solver is investigated by comparing the results with experimental data for two test problems and several flow conditions. Emphasis is placed on the sensitivity of the computed solution associated with turbulence modelling. The second aspect dealt with in the present paper concerns the extension of the numerical method to multi-element airfoils. Both, the block-structured and the unstructured grid approach are investigated in order to explore their specific merits and limitations. Detailed comparisons of the structured and unstructured approach are presented for low Reynolds number laminar viscous flows around a single airfoil, and for the inviscid flow around a multi-element airfoil.