Hostname: page-component-78c5997874-fbnjt Total loading time: 0 Render date: 2024-11-12T19:52:21.378Z Has data issue: false hasContentIssue false

The downstream flow beyond an obstacle

Published online by Cambridge University Press:  21 April 2006

P. M. Naghdi
Affiliation:
Department of Mechanical Engineering, University of California, Berkeley, Berkeley, California 94720 U.S.A.
L. Vongsarnpigoon
Affiliation:
Department of Mechanical Engineering, University of California, Berkeley, Berkeley, California 94720 U.S.A.

Abstract

This paper is concerned with theoretical predictions, given the upstream conditions from a rigid obstacle of arbitrary shape, of the downstream flow beyond the obstacle for an incompressible inviscid fluid sheet under the action of gravity. The fluid sheet flows upstream over a level bottom, continues to flow over (or under) an obstacle leading to a downstream region over a level bottom. In the absence of surface tension, a nonlinear st., ady-state solution of the problem is used to predict the downstream values of the free-surface wave height for the full range of the far-upstream Froude number. The general results obtained are then applied to a special case of fluid flowing over a stationary hump leading to a supercritical flow far downstream and detailed numerical comparison is made with available experimental results, with very good agreement.

Type
Research Article
Copyright
© 1986 Cambridge University Press

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Abramowitz, M. & Stegun, I. A. (ed.) 1965 Handbook of Mathematical Functions with Formulas, Graphs and Mathematics Tables. Dover.
Benjamin, T. B. 1956 On the flow in channels when rigid obstacles are placed in the stream. J. Fluid Mech. 1, 27248.Google Scholar
Benjamin, T. B. 1970 Upstream influence. J. Fluid Mech. 40, 4979.Google Scholar
Benjamin, T. B. & Lighthill, M. J. 1954 On cnoidal waves and bores. Proc. R. Soc. Lond. A 224,448–460.Google Scholar
Caulk, D. A. 1976 On the problem of fluid flow under a sluice gate. Intl J. Engng Sci. 14, 11151125.Google Scholar
Dressler, R. F. 1978 New nonlinear shallow-flow equations with curvature. J. Hydraulic Res. 16, 205220.Google Scholar
Green, A. E. & Naghdi, P. M. 1976a Directed fluid sheets. Proc. R. Soc. Lond. A 347, 447473.Google Scholar
Green, A. E. & Naghdi, P. M. 1976a A derivation of equations for wave propagation in water of variable depth. J. Fluid Mech. 78, 237246.Google Scholar
Green, A. E. & Naghdi, P. M. 1977 Water waves in a nonhomogeneous incompressible fluid. Trans. ASME E: J. Appl. Mech. 44, 523528Google Scholar
Henderson, F. M. 1966 Open Channel Flow. Macmillan.
Miles, J. & Salmon R. 1985 Weakly dispersive nonlinear gravity waves. J. Fluid Mech. 157,519–531.Google Scholar
Naghdi, P.M. 1979 Fluid jets and fluid sheets: a direct formulation. In Proc. 12th Symp. on Naval Hydrodynamics, pp. 500–515. National Academy of Sciences, Washington, D.C.
Naghdi, P. M. & Rubin, M. B. 1981 On the transition to planing of a boat. J. Fluid Mech. 103, 345374.Google Scholar
Naghdi, P. M. & Rubin, M. B. 1982 The effect of curvature at the detachment point of a fluid sheet from a rigid boundary. Phys. Fluids 25, 11101116.Google Scholar
Sivakumaran, N. S., Hosking, R. J. & Tingsanchali, T. 1981 Steady shallow flow over a spillway. J. Fluid Mech. 111, 411420.Google Scholar
Sivakumaran, N. S., Tingsanchali, T. & Hosking, R. J. 1983 Steady shallow flow over curved beds. J. Fluid Mech. 128, 469487.Google Scholar