Simple Model for Undertow Profile

Rattanapitikon, Winyu; Shibayama, Tomoya

doi:10.1142/s057856340000002x

Cited by 20 publications

(10 citation statements)

References 17 publications

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“…The undertow is driven by the incident-wave mass flux and the depth-dependent radiation stress; the profile shape is influenced by the bottom stress and vertical mixing. Various models have been developed to predict undertow (e.g., Svendsen and Lorenz, 1989; Garcez Faria et al, 2000; Rattanapitikon and Shibayama, 2000), often following the work of Svendsen (1984). Almost all of the models use the wave trough level as the cross-over location between onshore-and offshore-directed water fluxes.…”

Section: Vertical and Cross-shore Variations Of Timeaveraged Cross-shmentioning

confidence: 99%

Temporal and spatial variations of surf-zone currents and suspended sediment concentration

Wang

Ebersole

Smith

et al. 2002

Coastal Engineering

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Section: Vertical and Cross-shore Variations Of Timeaveraged Cross-shmentioning

confidence: 99%

Temporal and spatial variations of surf-zone currents and suspended sediment concentration

Wang

Ebersole

Smith

et al. 2002

Coastal Engineering

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“…Introduced by Svendsen et al (1978), the roller concept for depth-induced wave breaking accounts for the turbulent mass of mixed air and water advected by the breaker and the extra surface stresses that it generates, which affect the mean circulation (Bae et al, 2013;Deigaard, 1993;Deigaard & Fredsøe, 1989;Longuet-Higgins & Stewart, 1964;Nairn et al, 1990;Rattanapitikon & Shibayama, 2000;Stive & Wind, 1986;Svendsen, 1984;Svendsen et al, 1978). Unlike the eddy-viscosity approach mentioned above, the roller concept has the particular advantage that it provides both phase-resolving or phase-averaged models with a physical framework for parameterizing wave breaking processes in the surf zone.…”

Section: Introductionmentioning

confidence: 99%

Energy Dissipation in the Inner Surf Zone: New Insights From LiDAR‐Based Roller Geometry Measurements

et al. 2018

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The spatial and temporal variation of energy dissipation rates in breaking waves controls the mean circulation of the surf zone. As this circulation plays an important role in the morphodynamics of beaches, it is vital to develop better understanding of the energy dissipation processes in breaking and broken waves. In this paper, we present the first direct field measurements of roller geometry extracted from a LiDAR data set of broken waves to obtain new insights into wave energy dissipation in the inner surf zone. We use a roller model to show that most existing roller area formulations in the literature lead to considerable overestimation of the wave energy dissipation, which is found to be close to, but smaller than, the energy dissipation in a hydraulic jump of the same height. The role of the roller density is also investigated, and we propose that it should be incorporated into modified roller area formulations until better knowledge of the roller area and its link with the mean roller density is acquired. Finally, using previously published results from deepwater wave breaking studies, we propose a scaling law for energy dissipation in the inner surf zone, which achieves satisfactory results at both the time‐averaged and wave‐by‐wave scales.

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“…For a cross-shore current (undertow), the velocity profile may be considerably more complex. Applying the model by Rattanapitikon and Shibayama (2000) for the undertow profile, a mean current U c induces a maximum overestimation of the suspended load of about 20 percent compared to the theoretical profile. To conclude, it…”

Section: Validation Of Hypothesismentioning

confidence: 97%

A Unified Sediment Transport Formulation for Coastal Inlet Application

Camenen¹,

Larson²

2007

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Abstract:The Coastal Inlets Research Program (CIRP) is developing predictive numerical models for simulating the waves, currents, sediment transport, and morphology change at and around coastal inlets. Water motion at a coastal inlet is a combination of quasi-steady currents such as river flow, tidal current, wind-generated current, and seiching, and of oscillatory flows generated by surface waves. Waves can also create quasisteady currents, and the waves can be breaking or non-breaking, greatly changing potential for sediment transport. These flows act in arbitrary combinations with different magnitudes and directions to mobilize and transport sediment. Reliable prediction of morphology change requires accurate predictive formulas for sediment transport rates that smoothly match in the various regimes of water motion. This report describes results of a research effort conducted to develop unified sediment transport rate predictive formulas for application in the coastal inlet environment. The formulas were calibrated with a wide range of available measurements compiled from the laboratory and field and then implemented in the CIRP's Coastal Modeling System. Emphasis of the study was on reliable predictions over a wide range of input conditions. All relevant physical processes were incorporated to obtain greatest generality, including: (1) bed load and suspended load, (2) waves and currents, (3) breaking and non-breaking waves, (4) bottom slope, (5) initiation of motion, (6) asymmetric wave velocity, and (7) arbitrary angle between waves and current. A large database on sediment transport measurements made in the laboratory and the field was compiled to test different aspects of the formulation over the widest possible range of conditions. Other phenomena or mechanisms may also be of importance, such as the phase lag between water and sediment motion or the influence of bed forms. Modifications to the general formulation are derived to take these phenomena into account. The performance of the new transport formulation was compared to several popular existing predictive formulas, and the new formulation yielded the overall best predictions among the formulas investigated. Results of this report are thus considered to represent a significant and operational step toward a unified formulation for sediment transport at coastal inlets and the nearshore where transport of non-cohesive sediment is common.

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Simple Model for Undertow Profile

Cited by 20 publications

References 17 publications

Temporal and spatial variations of surf-zone currents and suspended sediment concentration

Temporal and spatial variations of surf-zone currents and suspended sediment concentration

Energy Dissipation in the Inner Surf Zone: New Insights From LiDAR‐Based Roller Geometry Measurements

A Unified Sediment Transport Formulation for Coastal Inlet Application

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