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Direct numerical simulation of wind-wave generation processes

Published online by Cambridge University Press:  10 December 2008

MEI-YING LIN
Affiliation:
Department of Civil Engineering, National Chiao Tung University, Hsinchu 30050, Taiwan Taiwan Typhoon and Flood Research Institute, Taichung 40763, Taiwan
CHIN-HOH MOENG*
Affiliation:
National Center for Atmospheric Research, Boulder, Colorado 80307, USA
WU-TING TSAI
Affiliation:
Department of Civil Engineering, National Chiao Tung University, Hsinchu 30050, Taiwan Institute of Hydrological Sciences, National Central University, Taoyuan 32001, Taiwan
PETER P. SULLIVAN
Affiliation:
National Center for Atmospheric Research, Boulder, Colorado 80307, USA
STEPHEN E. BELCHER
Affiliation:
Department of Meteorology, University of Reading, Earley Gate, PO Box 243, Reading RG6 6BB, UK
*
Email address for correspondence: [email protected]

Abstract

An air–water coupled model is developed to investigate wind-wave generation processes at low wind speed where the surface wind stress is about 0.089 dyn cm−2 and the associated surface friction velocities of the air and the water are u*a~8.6 cms−1 and u*w~0.3 cms−1, respectively. The air–water coupled model satisfies continuity of velocity and stress at the interface simultaneously, and hence can capture the interaction between air and water motions. Our simulations show that the wavelength of the fastest growing waves agrees with laboratory measurements (λ~8–12 cm) and the wave growth consists of linear and exponential growth stages as suggested by theoretical and experimental studies. Constrained by the linearization of the interfacial boundary conditions, we perform simulations only for a short time period, about 70s; the maximum wave slope of our simulated waves is ak~0.01 and the associated wave age is c/u*a~5, which is a slow-moving wave. The effects of waves on turbulence statistics above and below the interface are examined. Sensitivity tests are carried out to investigate the effects of turbulence in the water, surface tension, and the numerical depth of the air domain. The growth rates of the simulated waves are compared to a previous theory for linear growth and to experimental data and previous simulations that used a prescribed wavy surface for exponential growth. In the exponential growth stage, some of the simulated wave growth rates are comparable to previous studies, but some are about 2–3 times larger than previous studies. In the linear growth stage, the simulated wave growth rates for these four simulation runs are about 1–2 times larger than previously predicted. In qualitative agreement with previous theories for slow-moving waves, the mechanisms for the energy transfer from wind to waves in our simulations are mainly from turbulence-induced pressure fluctuations in the linear growth stage and due to the in-phase relationship between wave slope and wave-induced pressure fluctuations in the exponential growth stage.

Type
Papers
Copyright
Copyright © Cambridge University Press 2008

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References

REFERENCES

Al-Zanaidi, M. A. & Hui, W. H. 1984 Turbulent airflow over water waves – a numerical study. J. Fluid Mech. 148, 225246.Google Scholar
Aydin, E. M. & Leutheusser, H. J. 1991 Plane-Couette flow between smooth and rough walls. Exps. Fluids 11, 302312.Google Scholar
Belcher, S. E. & Hunt, J. C. R. 1993 Turbulent shear flow over slowly moving waves. J. Fluid Mech. 251, 109148.Google Scholar
Belcher, S. E., Newley, T. M. J. & Hunt, J. C. R. 1993 The drag on an undulating surface due to the flow of a turbulent layer. J. Fluid Mech. 249, 557596.CrossRefGoogle Scholar
Caulliez, G. & Collard, F. 1999 Three-dimensional evolution of wind waves from gravity–capillary to short gravity range. Eur. J. Mech. B/Fluids 13, 389402.CrossRefGoogle Scholar
Chandrasekhar, S. 1954 The character of the equilibrium of an incompressible heavy viscous fluid of variable density. Q. J. Mech. 162–178.Google Scholar
Cheung, T. K. & Street, R. L. 1988 The turbulent layer in the water at an air–water interface. J. Fluid Mech. 194, 133151.CrossRefGoogle Scholar
Choy, B. & Reible, D. D. 2000 Diffusion Model of Environmental Transport. Lewis.Google Scholar
Davis, R. E. 1970 On the turbulent flow over a wavy boundary. J. Fluid Mech. 42, 721731.CrossRefGoogle Scholar
De Angelis, V., Lombardi, P. & Banerjee, S. 1997 Direct numerical simulation of turbulent flow over a wavy wall. Phys. Fluids 9, 24292442.CrossRefGoogle Scholar
De Angelis, V. 1998 Numerical investigation and modeling of mass transfer processes at sheared gas–liquid interface. PhD thesis, UCSB.Google Scholar
van Duin, C. A. & Jassen, P. A. E. M. 1992 An analytic model of the generation of surface gravity waves by turbulent air flow. J. Fluid Mech. 236, 197215.CrossRefGoogle Scholar
Fulgosi, M., Lakehal, D., Banerjee, S. & De Angelis, V. 2003 Direct numerical simulation of turbulence in a sheared air–water flow with a deformable interface. J. Fluid Mech. 482, 319345.CrossRefGoogle Scholar
Gent, P. R. & Taylor, P. A. 1976 A numerical model of the air flow above water waves. J. Fluid Mech. 77, 105128.CrossRefGoogle Scholar
Henn, D. S. & Sykes, R. I. 1999 Large-eddy simulation of flow over wavy surface. J. Fluid Mech. 383, 75112.Google Scholar
Howe, B. M., Chambers, A. J., Klotz, S. P., Cheung, T. K. & Street, R. L. 1982 Comparison of profiles and fluxes of heat and momentum above and below an air–water interface. Trans. ASME C: J. Heat Transfer 104, 3439.Google Scholar
Jacobs, S. J. 1987 An asymptotic theory for the turbulent flow over a progressive wave. J. Fluid Mech. 174, 6980.CrossRefGoogle Scholar
Jeffreys, H. 1925 On the formation of water waves by wind. Proc. R. Soc. Lond. A 107, 189206.Google Scholar
Kahma, K. K. & Donelan, M. A. 1988 A laboratory study of the minimum wind speed for wind wave generation. J. Fluid Mech. 192, 339364.Google Scholar
Kawai, S. 1979 Generation of initial wavelets by instability of a coupled shear flow and their evolution to wind waves. J. Fluid Mech. 93, 661703.CrossRefGoogle Scholar
Kim, J., Moin, P. & Moser, R. 1987 Turbulence statistics in fully developed channel flow at low Reynolds number. J. Fluid Mech. 177, 133166.CrossRefGoogle Scholar
Kundu, P. K. 1990 Fluid Mechanics. Academic.Google Scholar
Larson, T. R. & Wright, J. W. 1975 Wind-generated gravity–capillary waves: laboratory measurements of temporal growth rates using microwave backscatter. J. Fluid Mech. 70, 417436.Google Scholar
Li, P. Y. 1995 A numerical study on energy transfer between turbulent air flow and finite amplitude water waves. PhD thesis, York University.Google Scholar
Lombardi, P., De Angelis, V. & Banerjee, S. 1996 Direct numerical simulation of near-interface turbulence in coupled gas–liquid flow. Phys. Fluids 8, 16431665.Google Scholar
Massel, S. R. 1996 Ocean Surface Waves: their Physics and Prediction. World Scientific.Google Scholar
Miles, J. W. 1957 On the generation of surface waves by shear flows. J. Fluid Mech. 3, 185204.CrossRefGoogle Scholar
Moin, P. & Mahesh, K. 1998 Direct numerical simulation: a tool in turbulence research. Annu. Rev. Fluid Mech. 30, 539578.Google Scholar
Papavassiliou, D. V. & Hanratty, T. J. 1997 Interpretation of large-scale structures observed in a turbulent plane Couette flow. Intl J. Heat Fluid Flow 18, 5569.Google Scholar
Phillips, O. M. 1957 On the generation of waves by a turbulent wind. J. Fluid Mech. 2, 417445.Google Scholar
Phillips, O. M. 1977 Dynamics of the Upper Ocean. Cambridge University Press.Google Scholar
Phillips, O. M. & Katz, E. J. 1961 The low frequency components of the spectrum of wind generated waves. J. Mar. Res. 19, 5769.Google Scholar
Plant, W. J. 1982 A relationship between wind stress and wave slope. J. Geophys. Res. 87, 19611967.CrossRefGoogle Scholar
Plate, E. J., Chang, P. C. & Hidy, G. M. 1969 Experiments on the generation of small water waves by wind. J. Fluid Mech. 35, 625656.Google Scholar
Spalart, P. R., Moser, R. D. & Rogers, M. M. 1991 Spectral methods for the Navier–Stokes equations with one infinite and two periodic directions. J. Comput. Phys. 96, 297324.CrossRefGoogle Scholar
Sullivan, P. P. & Mcwilliams, J. C. 2002 Turbulent flow over water waves in the presence of stratification. Phys. Fluids 14, 11821195.CrossRefGoogle Scholar
Sullivan, P. P., Mcwilliams, J. C. & Moeng, C. H. 2000 Simulation of turbulent flow over idealized water waves. J. Fluid Mech. 404, 4785.CrossRefGoogle Scholar
Sullivan, P. P., Mcwilliams, J. C. & Melville, W. K. 2004 The oceanic boundary layer driven by wave breaking with stochastic variability. Part 1. Direct numerical simulations. J. Fluid Mech. 507, 143174.CrossRefGoogle Scholar
Teixeira, M. A. C. & Belcher, S. E. 2006 On the initiation of surface waves by turbulent shear flow. Dyn. Atmos. Oceans 41, 127.CrossRefGoogle Scholar
Townsend, A. A. 1972 Flow in a deep turbulent boundary layer over a surface distorted by water waves. J. Fluid Mech. 55, 719735.Google Scholar
Townsend, A. A. 1980 Sheared turbulence and additional distortion. J. Fluid Mech. 98, 171191.CrossRefGoogle Scholar
Tsai, W.-T. 1998 A numerical study of the evolution and structure of a turbulent shear layer under a free surface. J. Fluid Mech. 354, 239276.CrossRefGoogle Scholar
Tsai, W.-T. & Yue, D. K. P. 1995 Effect of soluble and insoluble surfactant on laminar interactions of vortical flows with a free surface. J. Fluid Mech. 289, 315349.Google Scholar
Tsai, W.-T., Chen, S.-M. & Moeng, C.-H. 2005 A numerical study on the evolution and structure of a stress-driven free-surface turbulent shear flow. J. Fluid Mech. 545, 163192.CrossRefGoogle Scholar
Veron, F. & Melville, W. K. 2001 Experiments on the stability and transition of wind-driven water surfaces. J. Fluid Mech. 446, 2565.CrossRefGoogle Scholar
Wehausen, J. V. & Laitone, E. V. 1960 Surface waves. In Handbook of Physics, vol. 9, pp. 446778. Springer.Google Scholar