Accurate computation of drag for a wing/body configuration using multi-block, structered-grid CFD technology

In this report the contribution of the National Aerospace Laboratory NLR to the ’CFD Drag Pre- diction Workshop’ organized by the AIAA in Anaheim, CA, on June 9-10, 2001, is presented. This contribution consists of both the results of all test cases and a discussion on the accurate computation of drag coefficients. Two approaches are presented and discussed. The first method performs a grid convergence study using a sequence of nested grids yielding the grid-converged drag coefficient. To enable this study to be carried out, such a sequence of nested multi-block structured grids (’NLR’ grid) has been generated. The second method, using one grid only, de- composes the drag coefficient into its ’physical components’ (vortex, wave and viscous drag). As a consequence, this method provides the aerodynamic designer with a helpful tool, because of its diagnostic potential.