Two‐Equation Turbulence Model for Flow in Trenches

Steady recirculating flow is described by means of a mathematical model based on the full unsteady Reynolds equations and the K‐ε model for turbulence closure. The model is applied to the flow in a steep‐sided trench perpendicular to the main flow direction. Inlet profiles are taken with reference to developed channel flow. For the wall boundary a local equilibrium is assumed, yielding among others a logarithmic behavior for the mean flow velocity. The constants of the K‐ε model are related to the roughness conditions. A sensitivity study is reported to identify the relative importance of the various constants and inlet conditions. Numerical results are compared with laboratory experiments.