Effect of Stream Turbulence on Heater Water Plumes

by James Weil, U.S. Geological Survey, Menlo Park, CA,
Hugo B. Fischer, (M.ASCE), Assoc. Prof. of Civ. Engrg.; Univ. of California, Berkeley, CA, and Res. Hydr. Engr., U.S. Geological Survey,

Serial Information: Journal of the Hydraulics Division, 1974, Vol. 100, Issue 7, Pg. 951-970

Document Type: Journal Paper


The situation of a heated water surface jet flowing at the mean local velocity in open channel flow is studied. The jet contains no excess momentum that can cause mixing by relative motion of parallel streams. Downstream behavior is determined by buoyancy and ambient flow turbulence. Dimensional analysis determines the independent variables, x/D, d/D, u∗/un, and Fd, which are a distance ratio, a depth ratio, a friction factor, and a densimetric Froude number. In the range of study axis temperature is observed to be independent of d/D and Froude number, and only weakly dependent on u∗/uN. Results are shown for temperatures versus x/D. Mixing is significant, but dilution is less than for momentum jets in still water. Plume width due to buoy spread is shown to be (x/D)2/3, to (Fd)-2/3 (x/D2/3, with increased widths measured for increased turbulence. Results for layer depth are shown vs. x/D and are largely independent of d/D, u∗/un, and Fd.

Subject Headings: Rivers and streams | Turbulence | HVAC | Water management | Plumes | Jets (fluid) | Open channel flow | Froude number

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