This paper reports results of a comprehensive experimental investigation of inclined round dense jets in an otherwise stagnant fluid. The tracer concentration field is measured for six jet discharge angles: theta(o) = (15 degrees, 30 degrees, 38 degrees, 45 degrees, 52 degrees, & 60 degrees) and jet densimetric Froude number of Fr = 10-40 using the planar laser-induced fluorescence (LIF) technique; selected jet velocity measurements are made using Particle Image Velocimetry (Ply). The detailed jet mixing characteristics and turbulence properties are presented. The direct velocity measurement reveals that the mixing is jet-like until the maximum rise. Empirical correlations for the maximum jet rise height, jet dilution at maximum rise, and impact dilution are presented. Both the time-mean concentration and intermittency show that the upper jet edge spreading is similar to a positively buoyant jet; at the lower edge the buoyant instability induces significant detrainment and mass outflux for theta(o) > 15 degrees The dimensionless maximum rise height Z(max)/(FrD) is independent of source conditions for Fr >= 25, and varies from 0.44 for theta(o) = 15 degrees to 2.08 for theta(o) = 60 degrees Dilution measurements at terminal rise show the difference in dilution is small for 0 = 38 -60 and the asymptotic dilution constant is S-r/Fr = 0.45. The impact dilution S-i is also not sensitive to jet angle for theta(o) = 38 degrees-60 degrees and can be expressed as S-i/Fr = 1.06 for Fr >= 20. The Lagrangian jet model VISJET is used to interpret the experimental results. A detailed derivation for a general formulation of the entrainment coefficient is presented. Despite the observed detrainment, the trajectory and dilution are reasonably predicted; the maximum jet rise is generally under-predicted by 10-15% and associated dilution by 30%. However, the predicted variation of jet behavior with discharge angle is in good agreement with measurements. The experimental data is also compared with predictions of alternative models that employ an ad hoc entrainment hypothesis. (C) 2011 International Association for Hydro-environment Engineering and Research, Asia Pacific Division. Published by Elsevier B.V. All rights reserved.
