Simulation of plane impinging jets with k-ω based hybrid RANS/LES models

Plane impinging jets with nozzle-plate distances H/B = 10, 9.2 and 4 and Re = 13,500, 20,000 are simulated with k-ω based hybrid RANS/LES models and with a RANS k-ω model. The results are compared to experimental and LES data. Three different ways of substitution of the turbulent length scale by the local grid size in the LES mode of the hybrid RANS/LES models are tested. The results show that the hybrid models give much better prediction of the wall shear stress and the heat transfer rate along the impingement plate than the pure k-ω RANS model. The good performance of the hybrid models is due to their ability to resolve the evolution and break-up of the vortices in the shear layer of the jet, which strongly affects the turbulent flow and convective heat transfer in the stagnation region and the developing wall-jet region.