Frictional two-layer exchange flow

A numerical model is developed to study the effects of friction on the steady exchange flow that evolves when a barrier is removed from a constriction separating two reservoirs of slightly different densities. The model has excellent agreement with an analytical solution and laboratory measurements of exchange flows through channels of constant width and depth. The model reveals three viscous flow regimes for a convergent-divergent contraction of constant depth, and three additional viscous flow regimes when an offset sill is introduced. Each regime is characterized by a different set of internal hydraulic control locations. Examination of the predicted interface profiles reveals that it is not possible to distinguish between different flow regimes on the basis of these profiles alone.