Transitional flow on turbomachine blade using discontinuous Galerkin method

Large eddy simulation (LES) and a correlation-based transition model were applied with discontinuous Galerkin method (DGM) to investigate transitional flow on turbomachine blade.The methodology was used to simulate the flowfield within T106 turbine cascade and Zierke-Deutsch compressor cascade.Comparison was made between the results of transition model and LES for T106 cascade.The pressure distribution and the locations of separation bubbles calculated by the transition model and LES both agreed well with experimental results. The axial locations of separation bubbles predicted by LES and the transition model are 0.145~0.165m and 0.150~0.168m, respectively.The complex flow details,including the vortex structures in the separation bubble and the dynamic process of laminar separation,vortex shedding and wake diffusion,were simulated by LES,which can help to understand the transition mechanism.As for the transition model,although less flow details were captured,the calculated pressure distribution and the location of separation bubble agreed well with experimental data and LES results.The advantage of the transition model lies in the low computational costs,and it is more suitable for engineering applications.The accuracy of the transition model was further validated by the calculation of Zierke-Deutsch compressor cascade.