Verification of Anisotropic Mesh Adaptation for Unsteady Mixing and Reacting flow

Abstract

The recently proposed anisotropic mesh adaptation based on a Riemannian metric field is regarded as a promising approach to control the computational cost of computational fluid dynamics simulations. To ensure that computations of the aeroengine combustor have high fidelity and are cheap, this study extends anisotropic mesh adaptation to simulate unsteady mixing flow and turbulent combustion; it also verifies the results through comparison with a range of academic examples. Three grid-related components (metric building, metric-based grid generation, and solution interpolation) in conjunction with a large-eddy simulation solver based on the thickened flame model were used to implement anisotropic mesh adaptation. The results show the following: 1) The proposed mesh generation always led to a grid with high quality overall. 2) It has a remarkable capability to reduce computational cost while improving the numerical resolution. 3) A joint metric based on multiple fields should be used to ensure the accuracy of the computed velocity field and the interface between species. 4) The increase in computational cost incurred by grid-related operation was small enough to be ignored compared with the remarkable reduction in overall computational cost. 5) We simulated turbulent premixed combustion, and the statistical mean flows obtained were in good agreement with experimental measurements.