Development of a Discontinuous Galerkin Solver for High Quality Wall-Resolved/Modelled DNS and LES of Practical Turbomachinery Flows on Fully Unstructured Meshes

Abstract

The development of a high-order CFD solver for LES of turbomachinery is discussed. It is integrated in a flexible multiphysics platform Argo based on the discontinuous Galerkin Method. The DGM bridges the gap between the flexibility of the industrial solvers and the accuracy of the academic methods, as it is able to reach high order of accuracy on fully unstructured and hybrid meshes. Due to its inherent data locality, it also features high serial and parallel efficiency. The method provides a natural framework for adaptation of mesh size and interpolation order, which can be used later to further reduce computational cost and at the same time increase reliability of industrial DNS and LES. The paper mainly focuses on the physical modelling aspects and their interaction with the discretisation. In particular implicit LES and wall modelling is discussed. The approaches are tested on the wall-resolved and modelled LES of the turbulent channel flow. Finally the approach is applied to resolved LES of the near-transonic transitional flows in a low-pressure turbine cascade at Re = 9.4 × 104 and a compressor cascade at Re = 6.0 × 105. Either cases feature the full span and include end wall effects.