Embedded Large-Eddy Simulation Using the Partially Averaged Navier–Stokes Model

Artikel i vetenskaplig tidskrift, 2013

An embedded large-eddy-simulation modeling approach is explored and verified using the partially averaged Navier-Stokes model as a platform. With the same base model, the turbulence-resolving large-eddy simulation region is embedded by setting the partially averaged Navier-Stokes model coefficient to f(k) < 1 as distinguished from its neighboring Reynolds-averaged Navier-Stokes region, where f(k) = 1 is specified. The embedded large-eddy simulation 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 Reynolds-averaged Navier-Stokes/large-eddy simulation interface using anisotropic velocity fluctuations generated from synthetic turbulence. The effect of the spanwise size of the computational domain is investigated. It is shown that the embedded large-eddy-simulation method based on the partially averaged Navier-Stokes modeling approach is computationally feasible and able to provide reasonable turbulence-resolving predictions in the embedded large-eddy simulation region. The wall-adapting local eddy-viscosity model is also evaluated for the hump flow and it is found that its performance is worse than that of the the low-Reynolds-number partially averaged Navier-Stokes model when the results are compared with experiments.