FIELD OBSERVATIONS OF TURBULENCE OVER A GRAVEL BEACH

Zhi-Cheng Huang, Wu-Ting Tsai, Philip L.-F. Liu

Abstract


Field measurements of waves, current, and turbulence over a gravel beach are presented using dual ADVO techniques. Turbulence was decomposed using a filtering technique; the quality of the estimated turbulence was examined using ogive curve testing on turbulent shear stress (TSS) to remove wave biased containment. The turbulent dissipation rate was estimated using inertial subrange techniques. The ratio of the TSS to TKE is found to smaller than that in a current-alone flow, suggesting that transport of TKE into the bottom boundary layer (BBL) might be important. The turbulent dissipation rate is found to exceed the shear production, which also indicates the transport of TKE into the BBL might be important. After examining the most terms in the TKE budget as possible, we found that the observed vertical turbulent transport is comparable to the shear production, and contributes to part of gaining TKE in the BBL.

Keywords


gravel beach; turbulence; boundary layer; coastal zone.

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References


Conley, D.C. and Inman, D.L. 1992. Field observations of the fluid-granular boundary-layer under near-breaking waves, Journal of Geophysical Research-Oceans, 97(C6), 9631-9643.

Elgar, S., Raubenheimer, B. and Guza, R.T. 2005. Quality control of acoustic Doppler velocimeter data in the surf zone, Measurement Science & Technology, 16, 1889-1893.

Feddersen, F. 2012. Observations of the Surf-Zone Turbulent Dissipation Rate, Journal of Physical Oceanography, 42(3), 386-399.

Feddersen, F., Trowbridge, J.H. and Williams, A.J. 2007. Vertical structure of dissipation in the nearshore, Journal of Physical Oceanography, 37, 1764-1777.

Feddersen, F. and Williams, A.J. 2007. Direct estimation of the Reynolds stress vertical structure in the nearshore, Journal of Atmospheric and Oceanic Technology, 24(1), 102-116.

Foster, D.L., Beach, R.A. and Holman, R.A. 2000. Field observations of the wave bottom boundary layer, Journal of Geophysical Research-Oceans, 105(C8), 19631-19647.

Foster, D.L., Beach, R.A. and Holman, R.A. 2006. Turbulence observations of the nearshore wave bottom boundary layer, Journal of Geophysical Research-Oceans, 111(C4), C04011.

Grant, W.D. and Madsen, O.S. 1979. Combined wave and current interaction with a rough bottom, Journal of Geophysical Research-Oceans, 84(C4), 1979-1808.

Grant, W.D. and Madsen, O.S. 1986. The continental-shelf bottom boundary layer, Annual Review of Fluid Mechanics, 18, 265-305.

Grasso, F., Castelle, B. and Ruessink, B.G. 2012. Turbulence dissipation under breaking waves and bores in a natural surf zone, Continental Shelf Research, 43, 133-141.

Gross, T.F. and Nowell, A.R. 1983. Mean flow and turbulence scaling in a tidal boundary layer, Continental Shelf Research, 2, 109-126.

Huang, Z.C. et al. 2012. Dissipation of wave energy and turbulence in a barrier-reef lagoon, Journal of Geophysical Research-Oceans, 117, C03015.

Jones, N.L. and Monismith, S.G. 2008. The influence of whitecapping waves on the vertical structure of turbulence in a shallow estuarine embayment, Journal of Physical Oceanography, 38(7), 1563-1580.

Mori, N., Suzuki, T. and Kakuno, S. 2007. Noise of acoustic Doppler velocimeter data in bubbly flows, Journal of Engineering Mechanics-ASCE, 133(1), 122-125.

Perlin, A. et al. 2005. A modified law-of-the-wall applied to oceanic bottom boundary layers, Journal of Geophysical Research-Oceans, 110(C10), C10s10.

Pope, S.B. 2000. Turbulent flows. Cambridge Univ. Press, New York.

Reidenbach, M.A., Monismith, S.G., Koseff, J.R., Yahel, G. and Genin, A. 2006. Boundary layer turbulence and flow structure over a fringing coral reef, Limnology and Oceanography, 51(5), 1956-1968.

Reynolds, W.C. and 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.

Ruessink, B.G. 2010. Observations of Turbulence within a Natural Surf Zone, Journal of Physical Oceanography, 40(12), 2696-2712.

Sanford, T.B. and Lien, R.C. 1999. Turbulent properties in a homogeneous tidal bottom boundary layer, Journal of Geophysical Research-Oceans, 104(C1), 1245-1257.

Shaw, W.J. and Trowbridge, J.H. 2001. The direct estimation of near-bottom turbulent fluxes in the presence of energetic wave motions, Journal of Atmospheric and Oceanic Technology, 18(9), 1540-1557.

Smyth, C. and Hay, A.E. 2003. Near-bed turbulence and bottom friction during SandyDuck97, Journal of Geophysical Research-Oceans, 108, C63197.

Thompson, C.E.L., Williams, J.J., Metje, N., Coates, L.E. and Pacheco, A. 2012. Turbulence based measurements of wave friction factors under irregular waves on a gravel bed, Coastal Engineering, 63, 39-47.

Thornton, E.B. 1979. Energetics of breaking waves within the surf zone, Journal of Geophysical Research-Oceans and Atmospheres, 84(NC8), 4931-4938.

Trowbridge, J.H. and Agrawal, Y.C. 1995. Glimpses of a wave boundary-layer, Journal of Geophysical Research-Oceans, 100(C10), 20729-20743.

Walter, R.K., Nidzieko, N.J. and Monismith, S.G. 2011. Similarity scaling of turbulence spectra and cospectra in a shallow tidal flow, Journal of Geophysical Research-Oceans, 116, C10019.

Yoon, H.D. and Cox, D.T. 2010. Large-scale laboratory observations of wave breaking turbulence over an evolving beach, Journal of Geophysical Research-Oceans, 115, C10007.




DOI: https://doi.org/10.9753/icce.v34.currents.39