DLR Contributions to Code Validation Activities within the European High Lift Project EUROLIFT

Abstract

The contribution of DLR to the numerical flow simulation activities "assessment and improvement of CFD tools" of the European high lift project EUROLIFT is outlined. For the code assessment the DLR capabilities with respect to block-structured and Chimera grid generation for 2D and 3D high lift configurations are demonstrated, as well as to generate flow adapted hybrid unstructured grids for a 3D configuration. The corresponding results of 3D Navier-Stokes computations of aircraft configurations of different complexity show a good agreement of the DLR block-structured FLOWer code and the unstructured TAU code in comparison to experimental wind tunnel data up to maximum lift. Improvements of accuracy and efficiency in Navier-Stokes solvers are demonstrated by implementation of an advanced upwind discretization scheme and low speed preconditioning in the TAU code. The Chimera technique is used to evaluate the influence of the outer grid extension on the solution accuracy, and to improve the grid resolution in critical areas of complex 3D aircraft high lift configurations.