Asymptotic Solutions and Behavior of Outfall Plumes

Abstract
The simple model for a buoyant jet in a flow is presented. The model differs from those presently available in that it is forced to satisfy the limiting cases of a buoyant jet in still water, a nonbuoyant jet in a still fluid, a jet in a coflow, a momentum vortex, and an advected thermal. It reproduces these types of flow by using a spread constant both for the Gaussian and the vortex regions and using published data to determine criteria for the transition from the advected Gaussian to the advected vortex distributions. At the transition the minimum dilution for momentum and buoyancy flux are preserved. The flow from an infinite array of merging buoyant jets from an outfall diffuser is also discussed. When the ambient flow is stationary a method of obtaining a complete solution is outlined. When the cross flow is small the merged flow has the form of an advected two‐dimensional plume. For a larger cross flow the fluid becomes sufficiently stretched such that the lower stable surface is almost horizontal, whereas convective mixing occurs on the upper unstable surface. The number of merging outfall jets that are required for the central port to behave as if it were in an infinite array is 14 when the port spacing‐to‐diameter ratio is 18.

This publication has 16 references indexed in Scilit: