Interfacial Mixing Caused by Turbulent Buoyant Jets
Publication: Journal of Hydraulic Engineering
Volume 117, Issue 1
Abstract
Laboratory experiments were carried out to investigate mixing and entrainment induced by a planar turbulent buoyant jet impinging on a stable density interface. The jet was released horizontally into the homogeneous bottom layer of a fluid system in which the top linearly stratified layer was separated from the homogeneous layer by a density discontinuity. This flow configuration has similarities to those that occur in solar ponds and ocean thermal energy conversion plants. The results reveal markedly different entrainment mechanisms, and thus entrainment laws, for different jet regimes that depend on the inlet buoyancy of the jet. Measurements included the entrainment velocity, interfacial‐layer thickness, and time evolution of vertical density profiles. Based on observations of entrainment mechanisms, simple theoretical models are developed to predict entrainment laws for slightly buoyant and neutrally buoyant jet regimes, and the model predictions are compared with the experimental results.
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References
1.
Adams, E. E., et al. (1979). “Research on the external fluid mechanics of ocean thermal energy conversion plants.” Report No. MIT‐EL 79‐041, Energy Laboratory, Massachusetts Inst. of Technology, Cambridge, Mass.
2.
Baines, W. D. (1975). “Entrainment by plume or jet at a density interface.” J. Fluid Mech., 68, 309–320.
3.
Fernando, H. J. S., and Long, R. R. (1985). “On the nature of the entrainment interface of a two‐layer fluid subjected to zero‐mean‐shear turbulence.” J. Fluid Mech., 151, 21–53.
4.
Fischer, H. B., and List, E. J. (1979). Mixing in inland and coastal waters. Academic Press, New York, N.Y.
5.
E, X., and Hopfinger, E. J. (1986). “On mixing across interface in stably stratified fluid.” J. Fluid Mech., 166, 227–244.
6.
Hannoun, I. A., and List, E. J. (1988). “Turbulent mixing at a shear‐free density interface.” J. Fluid Mech., 189, 211–234.
7.
Johnstone, H. W. (1986). “Confined jet‐induced mixing at a density interface,” thesis presented to the University of Arizona, at Tucson, Arizona, in partial fulfillment of the requirements for the degree of Master of Science.
8.
Johnstone, H., and Zangrando, F. (1988). “Entrainment at a density interface driven by turbulent buoyant jet discharge and fluid recirculation.” Proc., 1st Nat. Fluid Dynamics Congress, AIAA‐88‐3724, 1776–1783.
9.
List, E. J. (1982). “Turbulent jets and plumes.” Annu. Rev. Fluid Mech., 14, 189–212.
10.
Long, R. R. (1978). “A theory of mixing in a stably stratified fluid.” J. Fluid Mech., 84, 113–124.
11.
Narimousa, S., and Fernando, H. J. S. (1987). “On the sheared density interface of an entraining stratified fluid.” J. Fluid Mech., 174, 1–22.
12.
Papanicolaou, P. N., and List, E. J. (1988). “Investigations of round vertical turbulent buoyant jets.” J. Fluid Mech., 195, 341–391.
13.
Phillips, O. M. (1977). Dynamics of the upper ocean. Cambridge University Press, Cambridge, England.
14.
Roberts, P. J. W., and Matthews, P. R. (1984). “Dynamics of jets in two‐layer stratified fluids.” J. Hydr. Engrg., ASCE, 110(9), 1201–1217.
15.
Roberts, P. J. W., and Matthews, P. R. (1987). “Behavior of low buoyancy jets in a linearly stratified fluid.” J. Hydr. Res., 25(4), 503–519.
16.
Schneider, H. H. (1980). “Laboratory experiments to simulate the jet‐induced erosion of pycnoclines in lakes.” Proc., Second Int. Symp. Stratified Flows, Trondheim, Norway, 697–706.
17.
Turner, J. S. (1973). Buoyancy effects in fluids. Cambridge University Press, Cambridge, England, 288–312.
18.
Zangrando, F. (1980). “A simple method to establish salt gradient solar ponds.” Solar Energy, 25(4), 467–470.
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Copyright © 1991 ASCE.
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Published online: Jan 1, 1991
Published in print: Jan 1991
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