Modeling Two-Dimensional Turbulent Offset Jets

Abstract

A two-dimensional unsteady simulation model is applied to the problem of a submerged turbulent offset jet. Numerical simulations and theoretical investigation are performed to gain insight into large-scale convective recirculation and flow processes in a waterbody induced by an offset jet. Jet behavior under various conditions with respect to boundary, offset ratio, and ambient are described in detail by directly modeling flow fields. Spatial and temporal distributions of velocity are simulated for various regions: deflection, recirculation, attachment, impingement, and wall-jet development. Predicted attachment distances, jet trajectories, and velocity profiles are presented and compared with laboratory experimental data for nonbuoyant offset jets to validate the model. Flow features are analyzed using model predictions along with existing data. Jet attachment to a free water surface is found to be similar to that to a solid wall. Largest velocity recovery occurs at an offset ratio in the range from 3 to 5. The results provide a better understanding of the flow characteristics of an offset jet and offer guidance for design of environmental water discharges.