Experimental and numerical study of the characteristics of thermal and nonthermal offset buoyant jets discharged into stagnant water.

This paper evaluates the effect of receiving water conditions on offset buoyant jet behavior. Several experiments on the discharge of thermal and nonthermal horizontal buoyant offset jets into stagnant ambient water are conducted. Particle Image Velocimetry (PIV) is used to measure the time history of the jet velocity distribution. Various characteristics of the jet flow, such as the centerline jet trajectory, jet growth rate and jet velocity decay, are discussed. All comparative experiments are conducted with the same densimetric Froude numbers (Fr_d ranging from 9.9 to 29.8) and density differences ∆ρ, ranging from 5.1 to 17.41). The results show that the trajectories of thermal jets are not the same as those of nonthermal jets, which suggests that thermal jets travel farther than nonthermal jets. The experimental results were then compared to predictions of three Reynolds-averaged Navier-Stokes (RANS) turbulence models: the standard k-ε, realizable k-ε, and buoyancy-modified k-ε. The best prediction of the centerline jet trajectory was found to be obtained from realizable k-ε. The study results revealed that the source of buoyancy (salinity versus temperature for the same values of Fr_d and same ∆ρ) affects the trajectory and mixing properties of the jet. [ABSTRACT FROM AUTHOR]