Hostname: page-component-76fb5796d-r6qrq Total loading time: 0 Render date: 2024-04-28T06:02:25.667Z Has data issue: false hasContentIssue false

A numerical model of the air flow above water waves

Published online by Cambridge University Press:  11 April 2006

P. R. Gent
Affiliation:
Department of Oceanography, University of Southampton, England
P. A. Taylor
Affiliation:
Department of Oceanography, University of Southampton, England

Abstract

A numerical model is proposed for the flow in a deep turbulent boundary layer over water waves. The momentum equations are closed by the use of an isotropic eddy viscosity and the turbulent energy equation. For small amplitudes the results are similar to those of Townsend's (1972) linear model, but nonlinear effects become important as the ratio of wave height to wavelength increases. With uniform surface roughness zo, the predicted fractional rate of energy input per radian advance in phase, ζ, decreases slightly with increasing amplitude and is of the same order of magnitude as in Miles’ (1957, 1959) and Townsend's linear theories. If zo is allowed to vary with position along the wave, however, the fractional rate of energy input can be significantly increased for small amplitude waves. If the variation in zo is half the mean value and the maximum wave slope zak is 0.01, we find ζ ≈ 60 (ρair/ρwater) (uo/c)2, where uo is the friction velocity and c the wave phase speed. Comparison is also made with recent laboratory and field data.

Type
Research Article
Copyright
© 1976 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

Barnett, T. P. & Kenyon, K. E. 1975 Rep. Frog. Phys. 38, 667.
Barnett, T. P. & Wilkerson, J. C. 1967 J. Mar. Res. 25, 292.
Benjamin, T. B. 1959 J. Fluid Mech. 6, 161.
Benney, D. J. & Bergeron, R. F. 1969 Studies in Appl. Math. 48, 181.
Bradshaw, P. 1973 Agardograph, no. 169.
Busch, N. E. 1973 Workshop on Micrometeorology (ed. Haugen). Boston: Am. Met. Soc.
Chorin, A. J. 1967 J. Comp. Phys. 2, 12.
Davis, R. E. 1969 J. Fluid Mech. 36, 337.
Davis, R. E. 1972 J. Fluid Mech., 52 287.
Dobson, F. W. 1971 J. Fluid Mech. 48, 91.
Elliott, J. A. 1972 J. Fluid Mech. 54, 427.
Hasselmann, K. et al. 1973 Dsch. Hydro. Z. Reihe A(8°), no. 12.
Hinze, J. O. 1959 Turbulence. McGraw-Hill.
Ieller, W. C. & Wright, J. W. 1976 Radio Bci. 10, 139.
Kendall, J. M. 1970 J. Fluid Mech. 41, 259.
Lamb, H. 1932 Hydrodynamics. Cambridge University Press.
Larson, T. R. & Wright, J. W. 1975 J. Fluid Meclb. 70, 417.
Long, R. B. 1971 Ph.D. thesis, University of Miami, Florida.
Longuet-Higgins, M. S. 1969a Proc. Roy. Soc. A 311, 371.
Longtjet-Higgins, M. S. 1969b Phys. Fluids, 12, 737.
Miles, J. W. 1957 J. Fluid Mech. 3, 185.
Miles, J. W. 1959 J. Fluid Mech. 6, 568.
Miles, J. W. 1967 J. Fluid Mech. 30, 163.
Phillips, O. M. 1966 The Dynamics of the Upper Ocean. Cambridge University Press.
Reynolds, W. C. & Hussain, A. K. M. F. 1972 J. Fluid Mech. 54, 263.Google Scholar
Sdmdin, O. H. 1969 Coastal Engng Lab., Univ. Florida, Tech. Rep. no. 4.
Shemdin, O. H. & Lai, R. J. 1973 Coastal Engng Lab., Univ. Florida, Tech. Rep. no. 18.
Snyder, R. L. 1974 J. Mar. Res. 32, 497.
Snyder, R. L. & Cox, C. S. 1966 J. Mar. Res. 24, 141.
Taylor, P. A., Gent, P. R. & Keen, J. M. 1976 Geophys. J. Roy. Astr. Soc. 44, 177.
Townsend, A. A. 1972 J. Fluid Mech. 55, 719.