Turbulent wake of a submerged flat plate

The turbulent wake of a two-dimensional, submerged flat plate is calculated by means of a parabolic, two-equation, k-epsilon model. The general turbulence model considered involves standard k and epsilon equations and possess the capability for free-surface proximity effect terms through an algebraic stress model for the Reynolds stress equation. This type of model along with an enhanced Dirichlet type boundary condition for the dissipation at the free surface has been successful in applications to open channel flow but it is found to be unsatisfactory for the submerged wake application. Both the proximity terms and the enhanced dissipation boundary condition lead to reduced wake drag when compared with recent experiments. A standard k-epsilon eddy viscosity model with adjusted model parameters and symmetric boundary conditions at the free-surface best describes the wake application. Model parameter sets for application to deep and shallow submerged wakes are optimized by comparing the predictions with the recent experiments of Swean and Keramidas. A parameter set with enhanced epsilon diffusivity and retarded k diffusivity seems to provide best agreement with the experimental profiles. The systematic wake drift toward the free-surface which has been observed experimentally is not predicted although excellent agreement is obtained when the predicted profiles are shifted in accordance with the experimental drift observations.