Bore Propagation Speed at the Termination of Wave Breaking

Okamoto, Takashi; Fortes, C. J. E. M.; Basco, David R.

doi:10.9753/icce.v32.waves.7

Cited by 7 publications

(10 citation statements)

References 11 publications

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“…The sign of the deviations in wave speeds from linear wave theory are consistent with the onshore shift in the location of the video-based cBathy sandbar (Fig. 8A), and with previous laboratory and field studies (Cat alan and Haller, 2008;Guza and Thornton, 1980;Thornton and Guza, 1982;Guza, 1985a, 1985b;Okamoto et al, 2010;Inman et al, 1971;Svendsen et al, 2003;Tissier et al, 2011;Postacchini and Brocchini, 2014). Over the year-long altimeter data set, video-derived wave speeds were up to 3 times linear theory values during storms (not shown).…”

Section: Errors In B H Ksupporting

confidence: 88%

“…Sources of error in cBathy include inaccurate parameter extraction from the imagery data and inaccurate representation of the physics (e.g., environmental conditions outside of the algorithm assumptions). For example, the linear dispersion relationship may be inaccurate as waves shoal and break in the surf zone, underestimating wave speeds by 20-40% (Holland, 2001;Cat alan and Haller, 2008;Guza and Thornton, 1980;Thornton and Guza, 1982;Elgar and Guza, 1985a;Okamoto et al, 2010). The implementation of linear theory in ) may be inaccurate as waves shoal and become nonlinear, as well as near the shoreline as waves break and transition to swash (Inman et al, 1971;Suhayda and Pettigrew, 1977).…”

Section: Introductionmentioning

confidence: 99%

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Evaluation of video-based linear depth inversion performance and applications using altimeters and hydrographic surveys in a wide range of environmental conditions

Brodie

Palmsten

Hesser

et al. 2018

Coastal Engineering

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The performance of a linear depth inversion algorithm, cBathy, applied to coastal video imagery was assessed using observations of water depth from vessel-based hydrographic surveys and in-situ altimeters for a wide range of wave conditions (0.3 < significant wave height < 4.3 m) on a sandy Atlantic Ocean beach near Duck, North Carolina. Comparisons of video-based cBathy bathymetry with surveyed bathymetry were similar to previous studies (root mean square error (RMSE) ¼ 0.75 m, bias ¼ À0.26 m). However, the cross-shore locations of the surfzone sandbar in video-derived bathymetry were biased onshore 18-40 m relative to the survey when offshore wave heights exceeded 1.2 m or were greater than half of the bar crest depth, and broke over the sandbar. The onshore bias was 3-4 m when wave heights were less than 0.8 m and were not breaking over the sandbar. Comparisons of video-derived seafloor elevations with in-situ altimeter data at three locations onshore of, near, and offshore of the surfzone sandbar over~1 year provide the first assessment of the cBathy technique over a wide range of wave conditions. In the outer surf zone, video-derived results were consistent with long-term patterns of bathymetric change (r 2 ¼ 0.64, RMSE ¼ 0.26 m, bias ¼ À0.01 m), particularly when wave heights were less than 1.2 m (r 2 ¼ 0.83). However, during storms when wave heights exceeded 3 m, video-based cBathy overestimated the depth by up to 2 m. Near the sandbar, the sign of depth errors depended on the location relative to wave breaking, with video-based depths overestimated (underestimated) offshore (onshore) of wave breaking in the surfzone. Wave speeds estimated by video-based cBathy at the initiation of wave breaking often were twice the speeds predicted by linear theory, and up to three times faster than linear theory during storms. Estimated wave speeds were half as fast as linear theory predictions at the termination of wave breaking shoreward of the sandbar. These results suggest that video-based cBathy should not be used to track the migration of the surfzone sandbar using data when waves are breaking over the bar nor to quantify morphological evolution during storms. However, these results show that during low energy conditions, cBathy estimates could be used to quantify seasonal patterns of seafloor evolution.

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Section: Errors In B H Ksupporting

confidence: 88%

Section: Introductionmentioning

confidence: 99%

Evaluation of video-based linear depth inversion performance and applications using altimeters and hydrographic surveys in a wide range of environmental conditions

Brodie

Palmsten

Hesser

et al. 2018

Coastal Engineering

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“…The wave passing time was calculated as the one corresponding to the largest cross-correlation value between the full records of each pair of gauges. This method was applied by Okamoto et al (2010). The full record of the wave gauges was used rather than sub-intervals of the same record.…”

Section: Wave Celeritymentioning

confidence: 99%

“…The traditional wave breaking indexes are usually related with the initial point of the wave breaking, leaving in background the end section of the process, which is, as mentioned above, especially important in coastal dynamics studies and for the set up of maritime structures. In addition, studies on wave breaking considering complex bathymetries (similar to real ones) and different incident wave conditions (according with real sea wave states) are always needed (Okamoto et al, 2010), since a great number of those studies is restricted to simplified bottom schemes and/or to a few incident wave conditions.…”

Section: Introductionmentioning

confidence: 99%

Directional spreading model in a wave channel: Wave propagation and wave breaking

et al. 2012

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This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues. Other uses, including reproduction and distribution, or selling or licensing copies, or posting to personal, institutional or third party websites are prohibited. In most cases authors are permitted to post their version of the article (e.g. in Word or Tex form) to their personal website or institutional repository. Authors requiring further information regarding Elsevier's archiving and manuscript policies are encouraged to visit: http://www.elsevier.com/copyright

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“…Following this reasoning, a wide range of wave flume tests was performed at the National Laboratory for Civil Engineering (LNEC) to study the wave transformation and breaking considering different incident conditions. Okamoto et al (2010), and performed a set of experimental tests for incident regular wave conditions originating wave breaking, considering different bottom slopes. The work presented in this paper follows the methodology of these previous works, considering incident regular waves without wave breaking.…”

Section: Introductionmentioning

confidence: 99%

Wave Propagation on a Flume: Physical Modelling

Conde

Reis

Fortes

et al. 2012

RETERM

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The knowledge of wave transformation and breaking characteristics near coastline is essential for the nearshore hydrodynamics and the design of coastal structures. This paper describes a wide range of wave flume tests performed at the National Laboratory for Civil Engineering (LNEC), located in Lisbon (Portugal), which main objective was to study wave shoaling and breaking over a set of different gentle slopes for several incident waves and thus to contribute for a better understand of the hydrodynamics of wave transformation.The experimental conditions, the measurement equipment, the incident wave characteristics, the type of measurements performed (free surface elevation and particle velocity) and the data obtained are described. Time and spectral analysis based upon the measured data are also performed and presented. For a regular wave with a period of 1.5s and a height of 0.1m are presented and discussed the following results: free surface elevation at selected sections along the flume; the spectral analysis; the significant wave height and average period along the flume; the particle velocity components at different locations along the flume; the average, maximum and minimum values of the longitudinal component of the velocity along the flume; the two dimensional distribution of the three components of the velocity; and longitudinal velocity component vertical profiles.

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Bore Propagation Speed at the Termination of Wave Breaking

Cited by 7 publications

References 11 publications

Evaluation of video-based linear depth inversion performance and applications using altimeters and hydrographic surveys in a wide range of environmental conditions

Evaluation of video-based linear depth inversion performance and applications using altimeters and hydrographic surveys in a wide range of environmental conditions

Directional spreading model in a wave channel: Wave propagation and wave breaking

Wave Propagation on a Flume: Physical Modelling

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