LABORATORY EXPERIMENTS OF BICHROMATIC WAVE GROUPS PROPAGATION ON A GENTLE SLOPE BEACH PROFILE AND ENERGY TRANSFER TO LOW AND HIGH FREQUENCY COMPONENTS
No. 35 (2016), Swash, Nearshore Currents, and Long Waves
No. 35 (2016)

LABORATORY EXPERIMENTS OF BICHROMATIC WAVE GROUPS PROPAGATION ON A GENTLE SLOPE BEACH PROFILE AND ENERGY TRANSFER TO LOW AND HIGH FREQUENCY COMPONENTS

Swash, Nearshore Currents, and Long Waves
https://doi.org/10.9753/icce.v35.currents.6
Published 2017-06-23
Enrique M Padilla
Imperial College London
http://orcid.org/0000-0003-0532-8809
Jose M Alsina
Imperial College London
http://orcid.org/0000-0002-3055-5379
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Keywords

Grouping waves
Bandwidth
Energy transfer

How to Cite

Padilla, E. M., & Alsina, J. M. (2017). LABORATORY EXPERIMENTS OF BICHROMATIC WAVE GROUPS PROPAGATION ON A GENTLE SLOPE BEACH PROFILE AND ENERGY TRANSFER TO LOW AND HIGH FREQUENCY COMPONENTS. Coastal Engineering Proceedings, 1(35), currents.6. https://doi.org/10.9753/icce.v35.currents.6
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Abstract

This work presents a first analysis of experimental data studying the influence of the frequency bandwidth on the propagation of bichromatic wave groups over a constant 1:100 beach slope. The use of a large spatial cross-shore resolution and Bi-Spectral analysis techniques allows the identification of nonlinear energy transfers along the propagation of wave groups. During wave-group shoaling, nonlinear coupling between the primary wave frequencies results in a larger growth of superharmonics for narrow-banded wave conditions, increasing the skewness of the wave and leading to eventual instabilities and earlier high frequency (hf) wave breaking compared to the broad-banded wave condition. Regarding the growth of low frequency (lf) component, the data analysis has shown a larger growth of the incident bound long wave (IBLW) for broad-banded wave conditions. It is generally assumed that the transferred energy from the primary wave components to subharmonics does not affect the short wave energy budget. Here, the opposite is hypothesised, and a larger growth of the IBLW for broad-banded wave conditions is accompanied of a larger reduction of the primary wave components, a reduced growth of hf components and, consequently, a reduction in the growth of hf wave asymmetry during wave group shoaling. Conversely for narrow-banded wave conditions, a reduced IBLW growth is associated with a larger growth of hf wave asymmetry. After hf wave breaking, within the low frequency domain (lf), the IBLW decays slightly for narrow-banded conditions, consistent with a reduction in radiation stress forcing. This involves a nonlinear energy transfer from the wave group frequency back to hf components. The remaining lf energy, Outgoing Free Long Wave (OFLW), reflects back at the shoreline. However, for broad-banded wave conditions, strong dissipation and minimal reflection of lf components occurs close to the shoreline, which might be caused by lf wave breaking.
https://doi.org/10.9753/icce.v35.currents.6
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References

Alsina, J. M., Padilla, E. M., and Cáceres, I. (2016). Sediment transport and beach profile evolution induced

by bi-chromatic wave groups with different group periods. Coastal Engineering 114, 325-340.

Baldock, T. E., Huntley, D. A., Bird, P. A. D., O'Hare, T., and Bullock, G. N. (2000). Breakpoint generated

surf beat induced by bichromatic wave groups. Coastal Engineering 39, 213-242.

Baldock, T. E. (2012). Dissipation of incident forced long waves in the surf zone - Implications for the

concept of "bound† wave release at short wave breaking. Coastal Engineering 60, 276-285.

Battjes, J. A., Bakkenes, H. J., Janssen, T. T., and Van Dongeren, A. R. (2004). Shoaling of subharmonic

gravity waves. Journal of Geophysical Research: Oceans 109(C2).

Bowers, E. C. (1977). Harbour resonance due to set-down beneath wave groups. Journal of Fluid Mechanics

, 71-92.

Collis, W. B., White, P. R., and Hammond, J. K. (1998). Higher-order spectra: the bispectrum and trispectrum.

Mechanical systems and signal processing 12(3), 375-394.

De Bakker, A. T. M., Tissier, M. F. S., and Ruessink, B. G. (2014). Shoreline dissipation of infragravity

waves. Continental Shelf Research 72, 73-82.

De Bakker, A. T. M., Herbers, T. H. C., Smit, P. B., Tissier, M. F. S., and Ruessink, B. G. (2015). Nonlinear

infragravity-wave interactions on a gently sloping laboratory beach. Journal of Physical Oceanography

(2), 589-605.

Doering, J. C., and Bowen, A. J. (1986). Shoaling surface gravity waves: A bispectral analysis. Proc. 20th

Int. Conf. Coastal Engineering, 150-162.

Doering, J. C., and Bowen, A. J. (1995). Parametrization of orbital velocity asymmetries of shoaling and

breaking waves using bispectral analysis. Coastal Engineering 26(1), 15-33.

Elgar, S., and Guza, R. T. (1985). Observations of bispectra of shoaling surface gravity waves. Journal of

Fluid Mechanics 161, 425-448.

Elgar, S., and Guza, R. T. (1986). Nonlinear model predictions of bispectra of shoaling surface gravity

waves. Journal of Fluid Mechanics 167, 1-18.

Hasselmann, K., Munk, W., and MacDonald, G. (1963). Bispectra of ocean waves. Time series analysis,

-139.

Henderson, S. M., Guza, R. T., Elgar, S., Herbers, T. H. C., and Bowen, A. J. (2006). Nonlinear generation

and loss of infragravity wave energy. Journal of Geophysical Research: Oceans, 111(C12).

Herbers, T. H. C., and Burton, M. C. (1997). Nonlinear shoaling of directionally spread waves on a beach.

Journal of Geophysical Research: Oceans 102(C9), 21101-21114.

Herbers, T. H. C., Russnogle, N. R., and Elgar, S. (2000). Spectral Energy Balance of Breaking Waves

within the Surf Zone. Journal of physical oceanography 30(11), 2723-2737.

Janssen, T. T., Battjes, J. A., and Van Dongeren, A. R. (2003). Long waves induced by short-wave groups

over a sloping bottom. Journal of Geophysical Research: Oceans, 108(C8).

List, J. H. (1992). A model for the generation of two-dimensional surf beat. Journal of Geophysical Research:

Oceans 97(C4), 5623-5635.

Longuet-Higgins, M. S., and Stewart, R. W. (1962). Radiation stress and mass transport in gravity waves,

with application to 'surf beats'. Journal of Fluid Mechanics 13, 481-504.

Phillips, O. M. (1960). On the dynamics of unsteady gravity waves of finite amplitude Part 1. The elementary

interactions. Journal of Fluid Mechanics 9, 193-217.

Ruessink, B. G., Kleinhans, M. G., and den Beukel, P. G. L. (1998). Observations of swash under highly

dissipative conditions. Journal of Geophysical Research: Oceans 103(C2), 3111-3118.

Ruessink, B. G., Van den Berg, T. J. J., and Van Rijn, L. C. (2009). Modeling sediment transport beneath

skewed asymmetric waves above a plane bed. Journal of Geophysical Research: Oceans, 114(C11).

Russell, P. E. (1993). Mechanisms for beach erosion during storms. Continental Shelf Research, 13(11),

-1265.

Sénéchal, N., Coco, G., Bryan, K. R., and Holman, R. A. (2011). Wave runup during extreme storm conditions.

Journal of Geophysical Research: Oceans, 116(C7).

Spinneken, J., and Swan, C. (2011). Theoretical transfer function for force-controlled wave machines. International

Journal of Offshore and Polar Engineering, 21(03).

Van Dongeren, A. R., and Svendsen, I. A. (1997). Quasi 3-D modeling of nearshore hydrodynamics (No.

CACR-97-04). Cent. for Appl. Coastal Res., Univ of Delaware, Nemark.

Van Dongeren, A. R., Battjes, J., Janssen, T. T., Van Noorloos, J., Steenhauer, K., Steenbergen, G., and

Reniers, A. J. H. M. (2007). Shoaling and shoreline dissipation of low-frequency waves. Journal of

Geophysical Research: Oceans, 112(C2).

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