Two-equation hybrid RANS-LES Models: A novel way to treat k and omega at the inlet

Paper i proceeding, 2015

A novel method for prescribing inlet conditions for $k$ and $\omega$ is presented and evaluated. The method is based on the proposal by Hamda to use commutation terms at RANS-LES interfaces. Commutation terms are added in the region near the inlet (i.e. the RANS-LES interface) in the k and omega equations. It is found that it is preferable to add the commutation terms only in the cells adjacent to the inlet. The commutation term in the k equation this term corresponds to a convection term where k is reduced from its RANS value to zero over one cell layer. Anisotropic synthetic fluctuations are used in the momentum equations as inlet conditions. The mean velocity, k, omega and the Reynolds shear stress profile are taken from a pre-cursor RANS simulation. The anisotropy of the synthetic fluctuations is defined from the EARSM model. No tuned constants are used.