Turbulent Jet Approach to Predict Expansion Head Loss at Submerged Outlets
Publication: Journal of Hydraulic Engineering
Volume 142, Issue 10
Abstract
As the flow expands at expansions, generation of turbulence by shear layers results in the dissipation of energy of the mean flow. Based on simplified momentum equations, this head loss was previously estimated to be comparable to the velocity head of the incoming flow. In this paper, an approach based on turbulent jet theories is used to more accurately evaluate head loss at outlets. This approach is based on the similarity between the generation of a shear layer at an outlet to that of a turbulent jet at its origin. A general equation is derived for the variation of the kinetic energy of the flow from outlets of any geometry and the corresponding head loss coefficient. The equation is simplified for rectangular outlets, which are more common in practice.
Get full access to this article
View all available purchase options and get full access to this article.
References
Abrahamsson, H., Johansson, B., and Löfdahl, L. (1997). “The turbulence field of a fully developed three-dimensional wall jet.”, Dept. of Thermo and Fluid Dynamics, Chalmers Univ. of Technology, Göteborg, Sweden.
Kells, J. A., and Smith, C. D. (1988). “Head recovery at submerged abrupt conduit outlets.” Can. J. Civ. Eng., 15(2), 272–274.
Launder, B. E., and Rodi, W. (1983). “The turbulent wall jet, measurements and modelling.” Ann. Rev. Fluid Mech., 15(1), 429–459.
Law, A. W. K., and Herlina (2002). “An experimental study on turbulent circular wall jets.” J. Hydraul. Eng., 161–174.
Liu, M., and Zhu, D. Z. (2000). “Study of tunnel outlet head-loss coefficient.” Can. J. Civ. Eng., 27(6), 1306–1310.
Rajaratnam, N. (1976). Turbulent jets, Elsevier, Amsterdam, Netherlands.
Rajaratnam, N., and Humphries, J. A. (1983). “Diffusion of bluff wall jets in finite depth tailwater.” J. Hydraul. Eng., 1471–1485.
Rajaratnam, N., and Muralidhar, D. (1969). “Flow below deeply submerged rectangular weirs.” IAHR J. Hydraul. Res., 7(3), 355–374.
Rajaratnam, N., and Pani, B. S. (1974). “Three-dimensional turbulent wall jets.” Proc. J. Hydraul. Div., 100(HY1), 69–83.
Rajaratnam, N., and Subramanya, K. (1967). “Diffusion of rectangular wall jets in wider channels.” IAHR J. Hydraul. Res., 5(4), 281–294.
Schall, J. D., Thompson, P. L., Zerges, S. M., Kilgore, R. T., and Morris, J. L. (2012). “Hydraulic design of highway culverts.”, Federal Highway Administration, U.S. Dept. of Transportation, Washington, DC.
Sforza, P. M., and Herbst, G. (1970). “A study of three-dimensional incompressible, turbulent wall jets.” AIAA J., 8(2), 276–283.
Simmons, W. P. (1964). “Transitions for canals and culverts.” J. Hydraul. Div., 90(HY3), 115–153.
Tullis, B. P., and Robinson, S. C. (2008). “Quantifying culvert exit loss.” J. Irrig. Drain. Eng., 263–266.
Information & Authors
Information
Published In
Journal of Hydraulic Engineering
Volume 142 • Issue 10 • October 2016
Copyright
© 2016 American Society of Civil Engineers.
History
Received: May 6, 2015
Accepted: Mar 22, 2016
Published online: Jun 6, 2016
Published in print: Oct 1, 2016
Discussion open until: Nov 6, 2016
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.