Unsteady RANS Computations of the Flow Past an Airfoil in the Wake of a Rod

Two-dimensional Reynolds Averaged Navier-Stokes (RANS) equations are solved in order to simulate the interaction between a Ka´rma´n vortex street shed from a rod and a NACA-0012 airfoil in the wake of the rod. Two closure turbulence models are tested, a linear and a nonlinear k-ω model, for a chord based Reynolds number Re_c ∼ 4.810⁵. These models provide consistent results in terms of both mean and fluctuating flow quantities. Insight into the instantaneous vorticity field shows that the vortex shedding pattern near the wall is quite well predicted, despite an over-estimated frequency. Downstream, computations always exhibit head-on interactions of the vortices with the airfoil leading edge whereas the experiments show a more variable configuration.