Hostname: page-component-77c89778f8-5wvtr Total loading time: 0 Render date: 2024-07-18T23:34:44.988Z Has data issue: false hasContentIssue false

Evolution of the turbulence structure in the surf and swash zones

Published online by Cambridge University Press:  28 January 2010

IN MEI SOU*
Affiliation:
Department of Civil and Environmental Engineering, University of Hawaii at Manoa, Honolulu, HI 96822, USA
EDWIN A. COWEN
Affiliation:
DeFrees Hydraulics Laboratory, School of Civil and Environmental Engineering, Cornell University, Ithaca, NY 14853, USA
PHILIP L.-F. LIU
Affiliation:
DeFrees Hydraulics Laboratory, School of Civil and Environmental Engineering, Cornell University, Ithaca, NY 14853, USA Institute of Hydrological and Oceanic Sciences, National Central University, Jhongli, Taoyuan 32001, Taiwan
*
Email address for correspondence: isou@hawaii.edu

Abstract

The velocity field and turbulence structure within the surf and swash zones forced by a laboratory-generated plunging breaking wave were investigated using a particle image velocimetry measurement technique. Two-dimensional velocity fields in the vertical plane from 200 consecutive monochromatic waves were measured at four cross-shore locations, shoreward of the breaker line. The phase-averaged mean flow fields indicate that a shear layer occurs when the uprush of the bore front interacts with the downwash flow. The turbulence characteristics were examined via spectral analysis. The larger-scale turbulence structure is closely associated with the breaking-wave- and the bore-generated turbulence in the surf zone; then, the large-scale turbulence energy cascades to smaller scales, as the turbulent kinetic energy (TKE) evolves from the outer surf zone to the swash zone. Smaller-scale energy injection during the latter stage of the downwash phase is associated with the bed-generated turbulence, yielding a −1 slope in the upper inertial range in the spatial spectra. Depth-integrated TKE budget components indicate that a local TKE equilibrium exists during the bore-front phases and the latter stage of the downwash phases in the outer surf zone. The TKE decay resembles the decay of grid turbulence during the latter stage of the uprush and the early stage of the downwash, as the production rate is small because of the absence of strong mean shear during this stage of the wave cycle as well as the relatively short time available for the growth of the bed boundary layer.

Type
Papers
Copyright
Copyright © Cambridge University Press 2010

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

REFERENCES

Battjes, J. A. 1974 Surf similarity. In Proceedings of the 14th Conference on Coastal Engineering, pp. 466480. ASCE.Google Scholar
Beach, R. A., & Sternberg, R. W. 1992 Suspended sediment transport in the surf zone: response to incident wave and longshore current interaction. Mar. Geol. 108, 275294.CrossRefGoogle Scholar
Chang, K.-A. & Liu, P. L.-F. 1999 Experimental investigation of turbulence generated by breaking waves in water of intermediate depth. Phys. Fluids 11, 33903400.CrossRefGoogle Scholar
Chen, D. & Jirka, G. H. 1995 Experimental study of plane turbulent wakes in a shallow water layer. Fluid Dyn. Res. 16, 1141.CrossRefGoogle Scholar
Cowen, E. A. & Monismith, S. G. 1997 A hybrid digital particle tracking velocimetry technique. Exp. Fluids 22, 199211.CrossRefGoogle Scholar
Cowen, E. A., Sou, I. M., Liu, P. L.-F. & Raubenheimer, B. 2003 Particle image velocimetry measurements within a laboratory generated swash zone. J. Engng Mech. 129, 11191129.Google Scholar
Cox, D. T., Hobensack, W. & Sukumaran, A. 2000 Bottom shear stress in the inner surf and swash zone. In Proceedings of the 27th International Conference of Coastal Engineering (ed. Edge, B. L.), pp. 108–119.Google Scholar
Davidson, P. A. 2004 Turbulence: An Introduction for Scientists and Engineers. Oxford University Press.Google Scholar
Dean, R. G. & Dalrymple, R. A. 1991 Water Wave Mechanics for Engineers and Scientists. World Scientific.CrossRefGoogle Scholar
Doron, P., Bertuccioli, L., Katz, J. & Osborn, T. R. 2001 Turbulence characteristics and dissipation estimates in the coastal ocean bottom boundary layer from PIV data. J. Phys. Oceanogr. 31, 21082134.2.0.CO;2>CrossRefGoogle Scholar
Efron, B. & Tibshirani, R. 1993 An Introduction to the Bootstrap. Chapman and Hall.CrossRefGoogle Scholar
Feng, T. & Stansby, P. K. 2005 Streamline topography in periodic surf zone waves from LDA measurements. Measure. Sci. Technol. 16, 19291936.CrossRefGoogle Scholar
George, R., Flick, R. & Guza, R. T. 1994 Observations of turbulence in the surf zone. J. Geophys. Res. 99, 801810.CrossRefGoogle Scholar
Hwung, H. H., Hwang, K. S., Chiang, W. S. & Lai, C. F. 1998 Flow structures in swash zone. In 26th International Conference on Coastal Engineering, Reston, VA.Google Scholar
Kraichman, R. H. 1967 Inertial ranges in two-dimensional turbulence. Phys. Fluids 11, 265277.Google Scholar
Mei, C. C. 1989 The Applied Dynamics of Ocean Surface Waves. World Scientific.Google Scholar
Melville, W. K., Veron, F. & White, C. J. 2002 The velocity field under breaking waves: coherent structures and turbulence. J. Fluid Mech. 454, 203233.CrossRefGoogle Scholar
Nadaoka, K. & Kondoh, T. 1982 Laboratory measurements of velocity field structure in the surf zone by LDV. Coastal Engng Jpn 25, 125145.CrossRefGoogle Scholar
Nikora, V. 1999 Origin of the −1 spectral law in wall-bounded turbulence. Phys. Rev. Lett. 83, 734736.CrossRefGoogle Scholar
Pedersen, C., Deigaard, R. & Sutherland, J. 1998 Measurements of the vertical correlation in turbulence under broken waves. Coastal Engng 35, 231249.CrossRefGoogle Scholar
Petti, M. & Longo, S. 2001 Turbulence experiments in the swash zone. Coastal Engng 43, 124.CrossRefGoogle Scholar
Pope, S. B. 2000 Turbulent Flows. Cambridge University Press.CrossRefGoogle Scholar
Puleo, J. A. & Holland, K. T. 2001 Estimating swash zone friction coefficient on a sandy beach. Coastal Engng 43, 2540.CrossRefGoogle Scholar
Raubenheimer, B., Elgar, S. & Guza, R. T. 2004 Observations of swash zone velocities: a note on friction coefficients. J. Geophys. Res. 109, C01027.CrossRefGoogle Scholar
Sou, I. M. 2006 An experimental investigation of the turbulence structure within the surf and swash zones. PhD dissertation, Cornell University, Ithaca, NY.Google Scholar
Stansby, P. K. & Feng, T. 2005 Kinematics and depth-integrated terms in surf zone waves from laboratory measurement. J. Fluid Mech. 529, 279310.CrossRefGoogle Scholar
Svendsen, I. A. 1987 Analysis of surf zone turbulence. J. Geophys. Res. 92, 51155124.Google Scholar
Taylor, G. I. 1938 The spectrum of turbulence. Proc. R. Soc. Lond. A 164, 476490.CrossRefGoogle Scholar
Tennekes, H. & Lumley, J. L. 1972 A First Course in Turbulence. MIT Press.CrossRefGoogle Scholar
Ting, F. C. K. & Kirby, J. T. 1994 Observation of undertow and turbulence in a laboratory surf zone. Coastal Engng 24, 5180.CrossRefGoogle Scholar
Ting, F. C. K. & Kirby, J. T. 1995 Dynamics of surf-zone turbulence in a strong plunging breaker. Coastal Engng 24, 177204.CrossRefGoogle Scholar
Ting, F. C. K. & Kirby, J. T. 1996 Dynamics of surf-zone turbulence in a spilling breaker. Coastal Engng 27, 131160.CrossRefGoogle Scholar
Uijttewaal, W. S. J. & Booij, R. 2000 Effects of shallowness on the development of free-surface mixing layers. Phys. Fluids 12, 392402.CrossRefGoogle Scholar
Uijttewaal, W. S. J. & Jirka, G. H. 2003 Grid turbulence in shallow flows. J. Fluid Mech. 489, 325344.CrossRefGoogle Scholar
Wereley, S. T. & Meinhart, C. D. 2001 Second-order accurate particle image velocimetry. Exp. Fluids 31, 258268.CrossRefGoogle Scholar
Westerweel, J. 1994 Efficient detection of spurious vectors in particle image velocimetry data sets. Exp. Fluids 16, 236247.CrossRefGoogle Scholar