Hybrid RANS-LES computations combine the benefits of RANS and LES so that LES is used in regions where the accuracy of RANS deteriorates. The numerous hybrid approaches are limited by the specification of the LES-RANS interface, which can cause nonphysical results such as log-layer mismatch and low shear stress. The hybrid RANS-LES approach based on the concept of model invariance, mitigates these problems, enabling seamless blending of the RANS and LES regions while forming the basis for interpreting the results in the interface region. This hybrid formulation was implemented in the NASA FUN3D unstructured code and computations for flow in a channel at Reynolds number of 3300 (based on the channel half width h and the centerline inflow velocity u_∞) were carried out. An isotropic stochastic turbulence generator was implemented to generate inflow turbulence. The present approach was able to eliminate the log-layer mismatch and predict the shear stress fairly well. Thus, the model-invariant hybrid formulation coupled with the isotropic turbulence inflow generation serves as a physically meaningful way of performing hybrid RANS-LES computations.
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