LES and URANS Computational Investigations of LPT Blade (L1A) Separation Control using Vortex Generator Jets

Abstract

This paper describes active flow control utilizing steady VGJs both experimentally and computationally for the L1A airfoil. URANS approach is compared with LES to test the ability to accurately predict effect of VGJs on the boundary layer separation. Cases were considered at Reynolds numbers (based on the suction surface length and the nominal exit velocity from the cascade) of 25,000, 50,000 and 100,000. In all cases without flow control, the boundary layer separated and did not reattach. The VGJs were successful in reducing the bubble size or removing it completely depending on the Re number and blowing ratio (B). Transition-sst RANS model was successful in predicting the flow separation and attachments with no jet flow. LES showed superior performance for the VGJs cases and much better agreement with the experimental data for the flow field at different values of Re and B