Initial Dilution Equations for Buoyancy-Dominated Jets in Current

Abstract

Initial dilution of submerged, single, round, buoyancy-dominated jets in a current is considered. Two simple semiempirical equations, one for centerline dilution and the other for minimum surface dilution, are presented. These equations are derived based on the continuity equation for the buoyant jet flow with a hypothesis that shear entrainment and forced entrainment can be added. Available laboratory and field data are used to determine the constants in the equations. Unlike asymptotic equations which apply for the limiting flow regimes, the proposed equations span all flow regimes, from the buoyancy-dominated near field (BDNF), to the transition, and to the buoyancy-dominated far field (BDFF), providing continuous predictions for dilutions.