Source Control of Intrusions along Horizontal Boundary

Abstract

The front of one fluid intruding into another along a horizontal boundary is generally analyzed by assuming that the interface far in the lee of the front is parallel if the effects of boundary and interfacial shear arc neglected. Depending on the conditions near the front and those near the intrusion source, hydraulic jumps or contraction waves can develop in the intermediate region, and the interface becomes nonhorizontal and unsteady. The conditions are established under which such disturbances can be maintained on the interface of air intrusions into a horizontal, water‐filled duct, and on gravity currents. In particular, it is shown that contraction waves and small jumps move towards the source of slender gravity currents that advance into an opposing flow of sufficient strength; experiments considered here suggest that the corresponding requirements remain satisfied over a wider range of flow conditions.