1-equation, 2-equation and Reynolds Stress Transport Modeling of Forward Facing Step Flow*

Turbulent forward facing step (FFS) flows arise in many aero/hydrodynamic engineering venues. These flows are characterized by complex non-equilibrium turbulence dynamics including unsteady separation upstream and downstream of the step leading edge. Accordingly, these systems have been studied experimentally by many workers. CFD methods have also been deployed for decades using turbulence modeling methods ranging from Reynolds Averaged Navier-Stokes (RANS) though resolved turbulence simulations.

In this work we apply a range of sublayer resolved RANS turbulence models to a configuration studied at The University of Calgary for an FFS protruding within on-coming boundary layer. Comparisons are made between predicted and measured mean velocity and Reynolds stresses, and modal energy budgets. Available Direct Numerical Simulation data are also used for comparison. Conclusions are drawn regarding the adequacy of 1-equation, 2-equation and 7-equation RANS models in characterizing these flows.