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Wave height

About: Wave height is a research topic. Over the lifetime, 5920 publications have been published within this topic receiving 100257 citations.


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Dissertation
01 Jun 2000
TL;DR: In this article, a non-linear theory and a numerical model solving the nonlinear shallow water equations (NLSW) were developed to model the physical process of non-breaking and breaking solitary waves on a smooth sloping beach.
Abstract: This study considers the run-up of non-breaking and breaking solitary waves on a smooth sloping beach. A non-linear theory and a numerical model solving the non-linear shallow water equations (NLSW) were developed to model this physical process. Various experiments to obtain wave amplitude time-histories, water particle velocities, wave free-surface profiles, and maximum run-up were conducted and the results were compared with the analytical and numerical models. A higher order theoretical solution to the non-linear shallow water equations, which describes the non-breaking wave characteristics on the beach, was sought and presented in this study. The solution was obtained analytically by using the Carrier and Greenspan (1958) hodograph transformation. It was found that the non-linear theory agreed well with experimental results. The maximum run-up predicted by the non-linear theory is larger than that predicted by Synolakis (1986) at the order of the offshore relative wave height for a given slope. This correction for non-breaking waves on beach decreases as the beach slope steepens, and increases as the relative incident solitary wave height increases. A unique run-up gage that consists of a laser and a photodiode camera was developed in connection with this study to measure the time-history of the tip of the run-up tongue of a non-breaking solitary wave as it progresses up the slope. The results obtained with this run-up gage agree well with other measurements and provides a simple and reliable way of measuring run-up time histories. The run-up of breaking solitary waves was studied experimentally and numerically since no fully theoretical approach is possible. The wave characteristics such as wave shape and shoaling characteristics, and, for plunging breakers, the shape of the jet produced are presented. The experimental results show that wave breaking is such a complicated process that even sophisticated numerical models cannot adequately model its details. Two different plunging wave breaking and resultant run-up were found from the experiments. The point, where the tip of the incident jet produced by the plunging breaking wave impinges determines the characteristics of the resulting splash-up. If the jet impinges on a dry slope, no splash-up occurs and the plunging breaker simply collapses. If the impingement point is located on the free-surface, splash-up including a reflected jet is formed, which further increases the turbulence and energy dissipation associated with wave breaking. It is hypothesized that both clockwise and counter clockwise vortices may be generated by the impinging plunging jet and the reflected jet associated with the splash-up when the jet impinges on the front face of a breaking wave or on the still water surface in front of the wave. If only the run-up process and maximum run-up are of interest, the wave and the water flow produced after breaking can be simplified as a propagating bore, which is analogous to a shock wave in gas dynamics. A numerical model using this bore structure to treat the process of wave breaking and propagation was developed. The non-linear shallow water equations were solved using the weighted essentially non-oscillatory (WENO) shock capturing scheme employed in gas dynamics. Wave breaking and propagation is handled automatically 1w this scheme and no ad-hoc term is required. A computational domain mapping technique proposed by Zhang (1996) is used in the numerical scheme to model the shoreline movement. This numerical scheme is found to provide a somewhat simple and reasonably good prediction of various aspects of the run-up process. The numerical results agree well with the experiments corresponding to the run-up on a. relatively steep slope (1:2.08) as well as on a more gentle slope (1:19.85). A simple empirical estimate of maximum run-up based on energy conservation considerations is also presented where the energy dissipation associated with wave breaking was estimated using the results from the numerical model. This approach appears to be useful and the maximum run-up predicted agrees reasonably well with the experimental results. The splash-up of a solitary wave on a vertical wall positioned at different locations on a gentle slope was also investigated in this study to understand the degree of protection from tsunamis afforded by seawalls. It was found that the effect of breaking wave kinematics offshore of the vertical wall on the splash-up is of critical importance to the maximum splash-up. The maximum slope of the front face of the wave upon impingement of the wave on the wall, which represents the maximum water particle acceleration, was important in defining the maximum sheet splash-up as well as the trend for splash-up composed of drops and spray.

170 citations

Journal ArticleDOI
TL;DR: A field experiment was conducted at Warraber Island, Torres Strait, Australia to investigate spatial and temporal variations in wave characteristics and energy across a mesotidal coral reef platform as mentioned in this paper.

169 citations

Journal ArticleDOI
TL;DR: In this paper, the authors present a simple method to estimate sediment erosion potential in shallow tidal basins caused by wind wave events, combining in a simple framework the contribution from different landscape units.
Abstract: [1] Wave-generated shear stresses are the main mechanism responsible for sediment erosion on tidal flats and regulate both sediment concentrations in the water column and, together with tidal currents, sediment export to salt marshes and to the ocean. We present herein a simple method to estimate sediment erosion potential in shallow tidal basins caused by wind wave events. The method determines the aggregate response of the entire basin, combining in a simple framework the contribution from different landscape units. The method is applied to a system of shallow tidal basins along the Eastern Shore of Virginia, USA. Our analysis unravels the interplay of basin morphology, tidal elevation, and wind direction on water depth, fetch, and the resulting wave-generated shear stresses. We identify four bottom shear stress regimes as a function of water elevation produced by wind waves in shallow micromesotidal systems. For water elevations below mean lower low water (MLLW), an increase in fetch is counteracted by an increase in depth, so that the average bottom shear stress and erosion potential is maintained constant. For elevations between MLLW and mean sea level (MSL), the increase in water depth dominates the increase in wave height, thus reducing the bottom shear stresses. For elevations between MSL and mean higher high water (MHHW), the range associated with stable salt marsh platforms, flooding of salt marshes increases fetch, wave height, and bottom shear stresses, producing the largest resuspension events in the bay. For elevations above MHHW, the increase in depth once again dominates increases in wave height, thereby reducing average bottom shear stresses and potential erosion.

169 citations

Journal ArticleDOI
Pierre Queffeulou1
TL;DR: In this paper, corrections for biases and trends are proposed for the six altimeters, allowing the generation of consistent and homogeneous data. Tests of these corrections are performed over global ocean simple statistics.
Abstract: Since July 1991, six altimeter missions have been launched successfully, and they have provided almost continuous wave height measurements for more than 12 years. Long-term series of wave height measurements are of major interest for climatology and oceanic wave modeling. Before using such data, the measurements have to be validated, and the homogeneity of the data from various satellites has to be checked. Significant wave height measurements from ERS, TOPEX/Poseidon, GEOSAT Follow-on, Jason-1 and ENVISAT altimeters are validated using cross-altimeter and buoy comparisons. Emphasis is put on the two recent missions Jason-1 and ENVISAT. Corrections for biases and trends are proposed for the six altimeters, allowing the generation of consistent and homogeneous data. Tests of these corrections are performed over global ocean simple statistics.

169 citations

Journal ArticleDOI
TL;DR: A coupled wave-circulation numerical model was used to simulate the distribution of wave energy, as well as the circulation induced by wave breaking, wind, and tidal forcing, within a coral reef system in Kaneohe Bay, Oahu, Hawaii as discussed by the authors.
Abstract: [1] A coupled wave-circulation numerical model was used to simulate the distribution of wave energy, as well as the circulation induced by wave breaking, wind, and tidal forcing, within a coral reef system in Kaneohe Bay, Oahu, Hawaii. Modeled wave, current, and wave setup fields were compared with field measurements collected on the forereef, reef flat, and reef channels and in the lagoon over a 4-week period. The predicted wave height transformation across the reef-lagoon system was in good agreement with field observations, using single-parameter (spatially uniform) values to describe both wave-breaking and frictional dissipation. The spatial distribution of the resulting wave setup field drove a persistent wave-driven flow across the reef flat that returned to the ocean through two deeper channels in the reef. Both the magnitude and direction of these currents were well described using a spatially uniform hydraulic roughness length scale. Notably, the model lends support to field observations that setup within the coastally bounded lagoon was a substantial fraction of the maximum setup on the reef (∼60–80%), which generated relatively weak cross-reef wave-driven flows (∼10–20 cm s−1) compared with reefs having mostly unbounded lagoons (e.g., many atolls and barrier reefs). Numerical experiments conducted using Lagrangian particle tracking revealed that residence times within Kaneohe Bay are extremely heterogeneous, typically ranging from 1 month within its sheltered southern lagoon.

166 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023166
2022326
2021251
2020262
2019272
2018242