Combined Oscillatory and Steady Flow over Ripples
Publication: Journal of Waterway, Port, Coastal, and Ocean Engineering
Volume 120, Issue 4
Abstract
Laser‐Doppler‐anemometer measurements of the fluid velocities in combined oscillatory and steady flow over rippled beds are reported. The direction of the steady current was parallel to the ripple crests and at right angles to the oscillatory flow. Measurements with the steady flow alone showed that the velocity distribution was quite well represented by the traditional logarithmic formula if height were replaced by a transformed coordinate η. It was not possible to detect a universal velocity distribution based directly on height above the local bed level. On the other hand, the combined flow measurements did not show good agreement with any existing formula in the immediate vicinity of the bed, although there was reasonable agreement with an existing formula further out. This formula also gave quite good prediction of the shear velocity in the combined flow. The importance of large‐scale momentum exchanges produced by vortex formation and ejection was demonstrated with reference to the fluctuation in velocity in the steady‐current direction.
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References
1.
Kemp, P. H., and Simons, R. R. (1982). “The interaction between waves and a turbulent current; Waves propagating with the current.” J. Fluid Mech., 116, 227–250.
2.
Kemp, P. H., and Simons, R. R. (1983). “The interaction between waves and a turbulent current; Waves propagating against the current.” J. Fluid Mech., 130, 73–89.
3.
Lee‐Young, J. S., and Sleath, J. F. A. (1988). “Initial motion in combined wave and current flows.” Proc. 21st Conf. on Coast. Engrg., ASCE, New York, N.Y.; 1140–1151.
4.
Motzfeld, H. (1937). “Die turbulente stromung an welligenden wanden.” ZAMM, 17, 193–212.
5.
Ranasoma, K. I. M., and Sleath, J. F. A. (1992). “Velocity measurements close to rippled beds.” Proc. 23rd Conf. on Coast. Engrg., ASCE, New York, N.Y.
6.
Simons, R. R., Grass, A. J., and Mansour‐Tehrani, M. (1992). “Bottom shear stresses in the boundary layer under combined waves and currents.” Proc. 23rd Conf. on Coast. Engrg., ASCE, New York, N.Y.
7.
Sleath, J. F. A. (1984). Sea bed mechanics. John Wiley and Sons, New York, N.Y.
8.
Sleath, J. F. A. (1990). “Velocities and bed friction in combined flows.” Proc. 22nd Conf. on Coast. Engrg., ASCE, New York, N.Y., 450–463.
9.
Sleath, J. F. A. (1991). “Velocities and shear stresses in wave‐current flows.” J. Geophys. Res. Oceans, 96(C8), 15237–15244.
10.
Swart, D. H. (1976). “Coastal sediment transport. Computation of longshore transport.” Report R968. Part I. Delft Hydr. Lab., Delft, The Netherlands.
11.
Van Doorn, T. (1981). “Experimental investigation of near bottom velocities in water waves with and without a current.” Report M1423, Delft Hydr. Lab., Delft, The Netherlands.
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Published In
Journal of Waterway, Port, Coastal, and Ocean Engineering
Volume 120 • Issue 4 • July 1994
Pages: 331 - 346
Copyright
Copyright © 1994 American Society of Civil Engineers.
History
Received: Apr 22, 1993
Published online: Jul 1, 1994
Published in print: Jul 1994
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