Buoyant Surface Jets

A combination of dimensional analysis, simple physical reasoning and data inspection is used to define distinct geometrical properties and mixing characteristics within the near field of buoyant surface jets. For deep stagnant receiving water, the jet has a transition length, a maximum penetration depth and a limited dilution capacity which is primarily met through bottom entrainment. These characteristics are found to scale with a densimetric Froude number based on kinematic momentum and buoyancy fluxes and a characteristic source length. A criterion for shallow water is developed based on observations of reduced entrainment; relationships for shallow water dilution and bottom attachment lengths are given. A criterion is presented to distinguish free and shoreline-attached jets in crossflowing receiving water, and a simple trajectory relationship appears to describe jet trajectories in crossflowing deep receiving water.