Turbulence anisotropy analysis in a highly loaded linear compressor cascade

Abstract

The aerodynamic performance of three-dimensional (3D) corner separation flow in a highly loaded compressor cascade has been investigated using Delayed Detached Eddy Simulation (DDES) based on SST k–ω turbulence model. Turbulence anisotropy of the 3D corner separation has been studied and the relationship between turbulence anisotropy and turbulence kinetic energy budget has been discussed. The Reynolds stress state has been studied, with particular attention in the corner separation region using the Anisotropy Invariant Map (AIM) theory. The analysis revealed that the turbulence anisotropy is high near the wall region initially and then decays gradually as the distance from the wall increases. The shape of Reynolds stress within the corner separation region tends to be rod-like. The anisotropy characteristics of various scale turbulence vortex structures are discussed through Reynolds stress anisotropy tensors (aij) and dissipation rate tensors (dij). Both the large and small scale turbulence vortex structures have shown a return-to-isotropy tendency far from the wall. It is found that the turbulence anisotropy is positively related to the turbulence kinetic energy budget.