A Dual -‐ Mesh Framework for Turbulence Modeling : Application to Flow Around a Circular Cylinder

To overcome this difficulty, various hybrid LES/RANS approaches have been developed, where RANS (Reynolds-averaged Navier-Stokes) equations are solved in the near-wall region while LES is only conducted in the free-shear region away from the wall [Fröhlich and von Terzi 2008]. One of the methods to address this issue is a consistent framework for turbulence modeling, where the filtered and Reynolds-averaged equations are solved simultaneously in the entire domain [Xiao and Jenny 2011]. To ensure consistency between the two solutions, additional drift terms are added to the corresponding equations. This approach leads to very clean conditions at the LES/RANS interfaces. According to this framework, a hybrid solver for incompressible turbulent flows has been implemented based on the open source CFD platform OpenFOAM [OpenFOAM 2011] taking advantage of its existing LES and RANS solvers as well as its field operation capabilities. The solver has been tested on plane channel flows and flow over periodic hills. To further validate the new simulation framework, the flow around a circular cylinder is investigated with the hybrid solver in this study.