Numerical modeling of 30 degrees and 45 degrees inclined dense turbulent jets in stationary ambient

摘要

Dispersion of turbulent jets in shallow coastal waters has numerous engineering applications. The accurate forecasting of the complex interaction of these jets with the ambient fluid presents significant challenge and has yet to be fully elucidated. In this paper, numerical simulation of 30 degrees and 45 degrees inclined dense turbulent jets in stationary water have been conducted. These two angles are examined in this study due to lower terminal rise heights for 30 degrees and 45 degrees, this is critically important for discharges of effluent in shallow waters compared to higher angles. Mixing behavior of dense jets is studied using a finite volume model (OpenFOAM). Five Reynolds-Averaged Navier-Stokes turbulence models are applied to evaluate the accuracy of CFD predictions. These models include two Linear Eddy Viscosity Models: RNG k - epsilon, and realizable k - epsilon; one Nonlinear Eddy Viscosity Model: nonlinear k - epsilon; and two Reynolds Stress Models: LRR and Launder-Gibson. Based on the numerical results, the geometrical characteristics of the dense jets, such as the terminal rise height, the location of centerline peak, and the return point are investigated. The mixing and dilution characteristics have also been studied through the analysis of cross-sectional concentration and velocity profiles. The results of this study are compared to various advanced experimental and analytical investigations, and comparative figures and tables are discussed. It has been observed that the LRR turbulence model as well as the realizable k - epsilon model predicts the flow more accurately among the various turbulence models studied herein.