| Turbulence was studied behind the wake of a flat plate using a commercial computational fluid dynamics (CFD) software package. Three turbulence models were highlighted, the k-epsilon, Reynolds Stress Model and Large Eddy simulation. Data were reported on two domains. The first encompassed the fluid region behind the plate, and the second included the actual physical plate in the domain. The RANS and LES models were able to accurately reproduce averaged velocity profiles in the near wake given only the inlet velocity, turbulent kinetic energy, and eddy dissipation. However, all three models failed to predict an accurate velocity profile in the far wake. Results based on the larger domain proved LES to be inferior using only data at the trailing edge, but superior using a plate with boundary layer trip, indicating LES was very sensitive to the selection of computational domain. The turbulence enhancing boundary layer trip was of utmost importance in triggering a fully developed velocity to mimic the physical experimental data. Numerical results also included plots of instantaneous data such as velocity vectors, vorticity, and RMS values. Evidence from the time averaged and instantaneous values showed that the mixing of the two flows coming from the plate surfaces was mainly through the streamwise vortices. Turbulence was most active around the interface between the two flows in the wake. Additionally, an asymmetric wake was examined. This wake was created using boundary layer trip of different sizes to create non-uniformity across the domain. An averaged and instantaneous characteristic comparison showed a large difference in the quantities between the symmetric and asymmetric profiles. |
