Evaluation of Navier‐Stokes and Euler solutions for leading‐edge separation vortices

Abstract

Abstract Extensive study on the numerical simulation of the vortical flow over a double‐delta wing is carried out using the ‘thin layer’ Navier‐Stokes and Euler equations. Two important flow characteristics, vortex interaction and vortex breakdown, are successfully simulated. Grid resolution is one of the most important factors associated with the vortex problem. Computations were performed on a series of grids with various levels of refinement, coarse, medium and fine. Computations using either the coarse or medium grids fail to capture the proper physical phenomena. The computed result using a fine grid shows flow unsteadiness once the vortex breakdown takes place. The C L ‐α characteristics are well predicted up to the breakdown angle of attack for all the grid distributions. The Euler solutions show fairly good agreement with experiment on the C L ‐α characteristics. However, other aspects of the solution at each angle of attack, such as the locus of the leading‐edge separation vortex, are not consistent with experiment. Even for the fine grid Navier‐Stokes computations, further grid resolution is required to obtain good quantitative agreement with experiment.