Scaling effects on the free surface backward facing step flow

A set of large eddy simulations for the free surface backward facing step (FSBFS) are carried out to study wave formation behind step. The volume-of-fluid ghost fluid method is employed capture surface. Previous studies have indicated that physics depend on draught-based Froude number (Fr). For small Fr, rear face (transom) becomes wet, while separates smoothly from transom. Close a critical Fr separating wet and dry transoms, both conditions may occur. Here, we critical, based classification with three different inflow boundary layer profiles ( ReL=1,2,3×106). = 1.75 (wet conditions), observe weak dependence ReL. proper orthogonal decomposition velocity field at shows coherent vortex street forming beneath At 2.66 (critical an increase in ReL results decrease wavelength pronounced gas entrainment due breaking. 3.17 (dry also shorter increased Further, conditions, breaking noticed occur higher ReL, waves not observed smallest studied Based results, conclude shape FSBFS cannot be characterized by alone.