The quality and convergence of any numerical flowfleld solution is inextricably linked to the quality of the mesh used. Structured meshes are normally accepted as being of higher quality than unstructured meshes, but are much more difficult to generate, and for complex topologies a multiblock approach is required. This is the most resource intensive approach to mesh generation, since block structures, mesh point distributions etc, need to be defined before the generation process, and so is seldom used in an industrial design loop, particularly where a novice user may be involved. This paper considers and presents two significant advances in multiblock mesh generation. First, the development of a fast, robust, and improved quality interpolation-based generation scheme and, second, a fully automatic multiblock optimisation and generation method. A volume generation technique is presented based on a form of transfinite interpolation, but modified to include improved orthogonality and spacing control near domain boundaries and, more significantly, an aspect ratio-based smoothing algorithm which removes grid crossover and results in smooth meshes even for discontinuous boundary distributions. A fully automatic multiblock generation scheme is also presented, which only requires surface patch(es) and a target number of mesh cells, and computes optimum grid spacing parameters and block structures from these. Hence, all user-input is removed from the process and a novice user is able to obtain a high quality mesh in a few minutes, and the code can be run in batch mode, or called as an external function, so is ideal for incorporating into a design or optimisation loop. Multiblock meshes are presented for wings, and rotors in hover and forward flight.
展开▼
