Relative Buoyancy Dominates Thermal-Like Flow Interaction along an Incline
Publication: Journal of Hydraulic Engineering
Volume 134, Issue 5
Abstract
This paper describes laboratory investigations of the motion between two fixed volumes of dense fluid (surge-type gravity currents) with different salt concentrations that interact above an incline in the presence of ambient stratification. The experiments include both large and small density contrasts between the interacting surges. Initially, the propagation of each fluid mass assumes a thermal-like nature, but then the lower density surge is quickly caught up by the denser fluid flow because of its higher velocity. There are two key process regarding the surge interaction. With a large density contrasting the fluid volumes, the denser flow moves to the front of the current as an intrusion with no mixing. With a small density difference, pronounced mixing occurs between the surges with the development of a homogeneous underflow. A simple energy parameterization is developed to evaluate the source conditions under which the different flow dynamics develop.
Get full access to this article
View all available purchase options and get full access to this article.
Acknowledgments
The writers are grateful to José Romero for comments on the earlier versions of this manuscript, and to the reviewers of this paper for their useful comments which have helped to improve the presentation of results. Financial support which made the laboratory experiments possible was provided by the Centre for Water Research. R.L. gratefully acknowledges an International Postgraduate Research Scholarship of the University of Western Australia during the time in which this work was performed.
References
Altinakar, S., Graf, W. H., and Hopfinger, E. J. (1990). “Weakly depositing turbidity current on a small slope.” J. Hydraul. Res., 28, 55–80.
Beghin, P., Hopfinger, E., and Britter, R. (1981). “Gravitational convection from instantaneous sources on inclined boundaries.” J. Fluid Mech., 107, 407–422.
Britter, R. E., and Linden, N. (1980). “Experiments on the dynamics of a gravity head.” J. Fluid Mech., 88, 223–240.
Fernandez, R., and Imberger, J. (2006). “Bed roughness induced entrainment in a high Richardson number underflow.” J. Hydraul. Res.,44(6), 725–738.
Fisher, H. B., List, E. J., Koh, R. C., Imberger, J., and Brooks, N. H. (1979). Mixing in inland and coastal waters, Academic, New York.
Gladstone, C., Ritchie, L. J., Sparks, R. S. J., and Woods, A. W. (2004). “An experimental investigation of density-stratified inertial gravity currents.” Sedimentology, 51, 767–789.
Graf, W. H., and Altinakar, M. S. (1995). “Courants de turbidité.” Houille Blanche, 7, 28–38.
Henderson, F. M. (1966). Open channel flow, Macmillan, New York.
Hopfinger, E. (1983). “Snow avalanche motion and related phenomena.” Annu. Rev. Fluid Mech., 15, 47–76.
Hürzeler, B., Imberger, J., and Ivey, G. (1996). “Dynamics of turbidity current with reversing buoyancy.” J. Hydraul. Eng., 122(5), 230–236.
Imberger, J. (1972). “Two-dimensional sink flow of a stratified fluid contained in a duct.” J. Fluid Mech., 43(2), 329–349.
Laval, A., Cremer, M., Beghin, P., and Ravenne, C. (1988). “Density surges: Two-dimensional experiments.” Sedimentology, 35, 73–84.
Long, R. R. (1955). “Some aspects of the flow of stratified fluids. III. Continuos density gradients.” Tellus, 7(3), 341–357.
Maxworthy, T., Leilich, J., Simpson, J., and Meiburg, E. H. (2002). “The propagation of a gravity current in a linearly stratified fluid.” J. Fluid Mech., 453, 371–394.
Morton, B. R., Taylor, G. I., and Turner, J. S. (1956). “Turbulent gravitational convection from maintained and instantaneous sources.” Proc. R. Soc. London, Ser. A, 234, 1–23.
Simpson, J. E. (1987). Gravity currents: In the environment and the laboratory, Cambridge University Press, Cambridge, U.K.
Information & Authors
Information
Published In
Journal of Hydraulic Engineering
Volume 134 • Issue 5 • May 2008
Pages: 636 - 643
Copyright
© 2008 ASCE.
History
Received: Jun 6, 2006
Accepted: Aug 16, 2007
Published online: May 1, 2008
Published in print: May 2008
Authors
Metrics & Citations
Metrics
Citations
Download citation
If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download.