Detached Eddy Simulation: Recent Development and Application to Compressor Tip Leakage Flow

Abstract

AbstractDetached eddy simulation (DES) and its variants are emerging tools for turbomachinery simulations. In this paper, the state-of-the-art upgrades of DES are reviewed, and their capabilities in predicting compressor tip leakage flow are discussed. The upgrade with the best potential is identified as the delayed DES (DDES) method with the grid spacing FKHΔhyb, which unlocks the physics of the Kelvin–Helmholtz instability in compressor tip leakage flow. The upgraded grid spacing FKHΔhyb is compared against the widely used default one Δmax in a backward-facing step and a low-speed axial compressor rotor. Results show that the DDES method with FKHΔhyb predicts both the main flow field and the turbulence field with reasonably good accuracy. However, the original DDES method with Δmax predicts a delayed transition to turbulence, which leads to an inaccurate prediction of the main flow field when using a coarse mesh. The findings in this paper highlight the future opportunities for using the DDES-FKHΔhyb method to predict tip-driven compressor stall and generate a turbulence database for turbulence model development.