Embedded LES Using PANS

Paper in proceeding, 2011

An embedded LES modelling approach is explored and verified using the PANS (Partially Averaged Navier-Stokes) model as a platform. With the same base model, the turbulence-resolving LES region is embedded by setting the PANS model coefficient to fk <l 1 as distinguished from its neighboring RANS region, where fk = 1 is specified. The embedded LES approach is verified in computations of a turbulent channel flow and a turbulent flow over a hump. Emphasis is placed on the impact of turbulent conditions at the RANS-LES interface using anisotropic velocity fluctuations generated from synthetic turbulence. The effects of model coefficient fk in the LES region, as well as of the span-wise size of the computational domain and the grid resolution in this direction, are also investigated. It is shown that the embedded LES method based on the PANS modelling approach is computationally feasible and able to provide reasonable turbulence-resolving predictions in the embedded LES region.