THE HYDRAULIC JUMP (SHOCKS AND VISCOUS-FLOW IN THE KITCHEN SINK)

The radial location and flow discontinuity of the hydraulic jump in a sink are discussed. The importance of viscosity in determining the loc ation of the jump is emphasized. A model, which highlights the importa nce of viscous flow near the sink surface, allows us to predict the ju mp radius and the flow depth on the upstream and downstream sides of t he jump as functions of viscosity, gravity, and flow velocity. In our approximate treatment, the jump location is independent of gravity and inversely proportional to the cube root of the viscosity.