Semi-Unstructured Mesh Generator for Flow Calculations in Axial Turbomachinery Blading

Abstract

This paper describes the development and application of a novel approach for discretizing turbomachinery blades by using a combination of structured and unstructured meshes, the former in the radial direction and the latter in the axial and tangential directions. The basic idea relies on the fact that blade-like structures are not strongly three dimensional since the radial variation is usually small. Compared with standard structured meshes for turbomachines, the proposed semi-unstructured grid demonstrates a significant improvement both in the smoothness of the grid-spacing and in resolving particular aspects of the passage geometry. Leading- and trailing-edge regions are discretized without generating superfluous points, while wake and shocks resolution can be obtained using a mesh refinement technique. The capability of the method is demonstrated using a semi-unstructured mesh for computing a steady-state viscous flow in a high pressure nozzleguide-vane and in a transonic fan.