Journal ArticleDOI
Shear instabilities of the mean longshore current: 2. Field observations
TLDR
In this article, a new wave with periods and alongshore wavelengths of the order of 102 seconds and meters, respectively, was observed in the surf zone and was consistent with a model of vorticity waves generated by the shear instability of the mean longshore current.Abstract:
A new type of alongshore progressive wave with periods and alongshore wavelengths of the order of 102 seconds and meters, respectively, has been observed in the surf zone. These periods fall into the lower end of the much studied infragravity frequency band previously shown to contain surface gravity edge and leaky waves. However, their short wavelengths (more than an order of magnitude smaller than the mode 0 edge wave) distinguish these new waves from surface gravity waves. In addition, they are only observed in the presence of mean longshore current and they change celerity (O(1 m/s)) and direction with the mean current. Alongshore wavenumber-frequency spectra clearly identify these waves, distinct from edge and leaky waves, by their approximately linear dispersion line at wavenumbers greater than the mode 0 edge wave dispersion curve. Their rms horizontal velocities can exceed 30 cm/s. These waves are shown to be consistent with a model [Bowen and Holman, this issue] of vorticity waves generated by the shear instability of the mean longshore current.read more
Citations
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Journal ArticleDOI
The history and technical capabilities of Argus
Robert A. Holman,J. Stanley +1 more
TL;DR: In this article, the authors describe the components of the Argus Stations with an emphasis on quantitative characterization of the accuracies and resolution of system components, and present algorithms for estimation of a range of important nearshore measurements.
Book
The Turbulent Ocean
TL;DR: The Turbulent Ocean as discussed by the authors describes the principal dynamic processes that control the distribution of turbulence, its dissipation of kinetic energy and its effects on the dispersion of properties such as heat, salinity, and dissolved or suspended matter in the deep ocean, the shallow coastal and the continental shelf seas.
Journal ArticleDOI
Morphodynamic modeling of an embayed beach under wave group forcing
TL;DR: In this article, the morphodynamic response of the nearshore zone of an embayed beach induced by wave groups is examined with a numerical model, which utilizes the nonlinear shallow water equations to phase resolve the mean and infragravity motions in combination with an advection-diffusion equation for the sediment transport.
Journal ArticleDOI
Hydrodynamics and sediment transport in the swash zone: a review and perspectives
Berry Elfrink,Tom E. Baldock +1 more
TL;DR: In this paper, the dominant hydrodynamic forcing and resulting sediment transport mechanisms in the swash zone are reviewed, combined with a discussion of future measurement and modelling requirements, and the strengths and weaknesses of different approaches identified.
Journal ArticleDOI
Bar/trough generation on a natural beach
TL;DR: In this article, velocities measured in the field applied to the Bowen [1980]/Bailard [1981] energetics-based sediment transport model were examined using velocity moments.
References
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Journal ArticleDOI
Swash oscillations on a natural beach
TL;DR: In this paper, run-up energy spectra at wind wave frequencies show an ƒ−3 dependence and energy levels that are independent of incident wave height, which suggests saturation.
Journal ArticleDOI
Shear instabilities of the mean longshore current: 1. Theory
TL;DR: Oltman-Shay et al. as discussed by the authors proposed a new class of nearshore waves based on the shear instability of a steady longshore current, which are longshore-progressive with celerities roughly equal to V0/3.
Journal ArticleDOI
Field observations of surf beat: 1. Progressive edge waves
TL;DR: In this article, 19 biaxial electromagnetic current meters were used to determine the longshore and on/offshore structure of currents at surf beat periods (1-4 min).
Journal ArticleDOI
Observations of surf beat
TL;DR: In this article, measured surf beat run-up spectra are coupled with numerical integrations of the long wave equations to predict the energy spectrum at offshore sensors, and the coherence and phase between offshore sensors and runup meter.
Journal ArticleDOI
Infragravity Edge Wave Observations on Two California Beaches
Joan Oltman-Shay,Robert T. Guza +1 more
TL;DR: In this paper, a wave velocity field in the surf zone of two California beaches is estimated using a biaxial electromagnetic current meters (BEM) and model testing provides insight into the limits, capabilities and reliability of the estimators.