THE NEAR-FIELD JET BEHAVIOR OF 60° DENSE JETS DISCHARGED INTO A PERPENDICULAR CROSSFLOW

Wastewater effluents with a density higher than that of the environment are often discharged into coastal waters in the form of submerged dense jets. Examples include brine discharge from desalination plants and cooled water from liquefied natural gas plants. In general, there exists an ambient current which can approach the jet at an arbitrary angle; the resulting dense jet will then have a three-dimensional trajectory. We present an experimental investigation on 60 degrees dense jets discharged into a perpendicular current. The tracer concentration field is measured at selected cross-sections using the Laser induced-fluorescence (LIF) method. Jet detrainment from the dense jet is observed; the detrained jet fluid is advected horizontally downstream by the crossflow. Compared to predictions of a validated integral jet model that does not account for jet detrainment, it is found that the horizontal jet penetration in the momentum plane is consistently under-predicted by about 35 percent, while the jet trajectory in the buoyancy plane and the near field dilution in the bent-over dense jet are reasonably well-predicted.