Detailed knowledge of the airflow over the surface of the ocean is paramount to evaluate and predict air-sea fluxes. The flux of momentum is of particular interest because it involves phenomena over a large spectrum of length and temporal scales from aerodynamic drag in large storm systems, down to the wind-wave generation problem at sub-centimeter scales. At the smaller scales, while there is a body of theoretical and experimental work which suggests that the wind-wave generation process is linked to the instability of the coupled air-water surface flow, progress has been hindered by the difficulties associated with making reliable measurements or simulations near the air-water interface at scales at which viscosity plays a role. In this paper, we present recent measurements of the two-dimensional velocity field in the turbulent airflow above wind waves. Improvements in measuring techniques have allowed us to detect the viscous sublayer in the airflow near the interface and make direct measurements of the airside viscous tangential stress (analogous to those made by (Banner ML, Peirson WL, J Fluid Mech 364:115–145, 1998) on the water side). Furthermore, we were able to separate mean, turbulent, and wave-coherent motions, and this decomposition yielded wave-coherent flow measurements as well as wave-phase averages of several flow field variables. We present the relationship of the varying surface viscous stress with the dominant wave phase. Also, to the authors’ knowledge, we present the first measurements of airside wave-induced viscous stresses. We conclude that at low wind speed, surface viscous effects are substantial and likely need to be accounted for in the early stages of the wind-wave generation process.
This is a preview of subscription content, access via your institution.
Tax calculation will be finalised at checkout
Purchases are for personal use onlyLearn about institutional subscriptions
Banner, M. L., & Peirson, W. L. (1998). Tangential stress beneath wind-driven air-water interfaces. Journal of Fluid Mechanics, 364, 115–145.
Bopp, M. (2018). Air-flow and stress partitioning over wind waves in a linear wind-wave facility (Doctoral dissertation), Heidelberg: Heidelberg University.
Buckley, M. P., (2015). Structure of the airflow above surface waves. (Doctoral dissertation), Newark: University of Delaware.
Buckley, M. P., & Veron, F. (2016). Structure of the airflow above surface waves. Journal of Physical Oceanography, 46(5), 1377–1397.
Buckley, M. P., & Veron, F. (2017). Airflow measurements at a wavy air–water interface using PIV and LIF. Experiments in Fluids, 58(11), 161.
Buckley, M. P., & Veron, F. (2019). The turbulent airflow over wind generated surface waves. European Journal of Mechanics - B/Fluids, 73, 132–143.
Csanady, G. (1985). Air-sea momentum transfer by means of short-crested wavelets. Journal of Physical Oceanography, 15(11), 1486–1501.
Csanady, G. (1990). Momentum flux in breaking wavelets. Journal of Geophysical Research: Oceans, 95(C8), 13289–13299.
Gent, P. R., & Taylor, P. A. (1976). A numerical model of the air flow above water waves. Journal of Fluid Mechanics, 77, 105–128.
Gent, P. R., & Taylor, P. A. (1977). A note on separation over short wind waves. Boundary-Layer Meteorology, 11(1), 65–87.
Grare, L., Lenain, L., & Melville, W. K. (2013a). Wave-coherent airflow and critical layers over ocean waves. Journal of Physical Oceanography, 43(10), 2156–2172.
Grare, L., Peirson, W. L., Branger, H., Walker, J. W., Giovanangeli, J. P., & Makin, V. (2013b). Growth and dissipation of wind-forced, deep-water waves. Journal of Fluid Mechanics, 722, 5–50.
Hara, T., & Belcher, S. E. (2004). Wind profile and drag coefficient over mature ocean surface wave spectra. Journal of Physical Oceanography, 34(11), 2345–2358.
Hara, T., & Sullivan, P. P. (2015). Wave boundary layer turbulence over surface waves in a strongly forced condition. Journal of Physical Oceanography, 45(3), 868–883.
Hsu, C. T., Hsu, E. Y., & Street, R. L. (1981). On the structure of turbulent flow over a progressive water wave: Theory and experiment in a transformed, wave-following coordinate system. Journal of Fluid Mechanics, 105, 87–117.
Hussain, A. K. M. F., & Reynolds, W. C. (1970). The mechanics of an organized wave in turbulent shear flow. Journal of Fluid Mechanics, 41, 241–258.
Husain, N. T., Hara, T., Buckley, M. P., Yousefi, K., Veron, F., & Sullivan, P. P. (2019). Boundary layer turbulence over surface waves in a strongly forced condition: LES and observation. Journal of Physical Oceanography, 49(8), 1997–2015.
Kawamura, H., & Toba, Y. (1988). Ordered motion in the turbulent boundary layer over wind waves. Journal of Fluid Mechanics, 197, 105–138.
Kihara, N., Hanazaki, H., Mizuya, T., & Ueda, H. (2007). Relationship between airflow at the critical height and momentum transfer to the traveling waves. Physics of Fluids, 19(1), 015102.
Kudryavtsev, V. N., & Makin, V. K. (2001). The impact of air-flow separation on the drag of the sea surface. Boundary-Layer Meteorology, 98(1), 155–171.
Longuet-Higgins, M. S. (1969). Action of a variable stress at the surface of water waves. Physics of Fluids, 12(4), 737–740.
McLeish, W., & Putland, G. E. (1975). Measurements of wind-driven flow profiles in the top millimeter of water. Journal of Physical Oceanography, 5(3), 516–518.
Okuda, K., Kawai, S., & Toba, Y. (1977). Measurement of skin friction distribution along the surface of wind waves. Journal of Oceanography, 33(4), 190–198.
Peirson, W. L. (1997). Measurement of surface velocities and shears at a wavy air–water interface using particle image velocimetry. Experiments in Fluids, 23(5), 427–437.
Peirson, W. L., & Banner, M. L. (2003). Aqueous surface layer flows induced by microscale breaking wind waves. Journal of Fluid Mechanics, 479, 1–38.
Peirson, W. L., Walker, J. W., & Banner, M. L. (2014). On the microphysical behavior of wind-forced water surfaces and consequent re-aeration. Journal of Fluid Mechanics., 743, 399–447.
Phillips, O. M. (1977). The dynamics of the upper ocean (2nd ed.). Cambridge/London/New York/Melbourne: Cambridge University Press.
Reul, N., Branger, H., & Giovanangeli, J. P. (2008). Air flow structure over short-gravity breaking water waves. Boundary-Layer Meteorology, 126(3), 477–505.
Reynolds, W. C., & Hussain, A. K. M. F. (1972). The mechanics of an organized wave in turbulent shear flow. Part 3. Theoretical models and comparisons with experiments. Journal of Fluid Mechanics, 54, 263–288.
Shen, L., Zhang, X., Yue, D. K. P., & Triantafyllou, M. S. (2003). Turbulent flow over a flexible wall undergoing a streamwise travelling wave motion. Journal of Fluid Mechanics, 484, 197–221.
Sullivan, P. P., McWilliams, J. C., & Moeng, C. H. (2000). Simulation of turbulent flow over idealized water waves. Journal of Fluid Mechanics, 404, 47–85.
Thomas, M., Misra, S., Kambhamettu, C., & Kirby, J. T. (2005). A robust motion estimation algorithm for PIV. Measurement Science and Technology, 16(3), 865.
Veron, F., Saxena, G., & Misra, S. K. (2007). Measurements of the viscous tangential stress in the airflow above wind waves. Geophysical Research Letters, 34(19), L19603.
Yang, D. I., & Shen, L. (2010). Direct-simulation-based study of turbulent flow over various waving boundaries. Journal of Fluid Mechanics, 650, 131–180.
We wish to sincerely thank Ed Monahan for inviting us to participate, with this modest contribution, in the Festschrift celebrating his 83rd birthday. Ed has had a long, remarkable, and distinguished career, greatly influencing the field of air-sea interaction, and providing landmark contributions on many challenging problems through innovative ideas and keen physical interpretations. In particular, he is probably most well-known for his seminal work on white cap coverage, and on the generation of sea spray. His work has had indeed a profound influence on the field, opening new research avenues, and inspiring generations of scientists. We are truly honored to be invited to celebrate Ed’s birthday. Ed, we wish you a happy birthday!
This research was supported by the National Science Foundation (NSF) through grant numbers OCE 0748767, OCE-1458977, and OCE-1634051.
Editors and Affiliations
© 2020 Springer Nature Switzerland AG
About this chapter
Cite this chapter
Yousefi, K., Veron, F., Buckley, M.P. (2020). Measurements of Airside Shear- and Wave-Induced Viscous Stresses over Strongly Forced Wind Waves. In: Vlahos, P., Monahan, E. (eds) Recent Advances in the Study of Oceanic Whitecaps. Springer, Cham. https://doi.org/10.1007/978-3-030-36371-0_6
Publisher Name: Springer, Cham
Print ISBN: 978-3-030-36370-3
Online ISBN: 978-3-030-36371-0