scholarly journals The dynamics of infragravity wave transformation over a fringing reef

2012 ◽  
Vol 117 (C11) ◽  
pp. n/a-n/a ◽  
Author(s):  
Andrew Pomeroy ◽  
Ryan Lowe ◽  
Graham Symonds ◽  
Ap Van Dongeren ◽  
Christine Moore
Keyword(s):  
Wave Transformation ◽  
Fringing Reef ◽  
Infragravity Wave

scholarly journals UNDULAR BORE DEVELOPMENT OVER A LABORATORY FRINGING REEF

2018 ◽  
pp. 53 ◽  
Author(s):  
Marion Tissier ◽  
Jochem Dekkers ◽  
Ad Reniers ◽  
Stuart Pearson ◽  
Ap Van Dongeren
Keyword(s):  
Coral Reefs ◽  
Wave Field ◽  
Reef Flat ◽  
Wave Transformation ◽  
Undular Bore ◽  
Fringing Reef ◽  
Long Wave ◽  
Reef Type ◽  
Run Up ◽  
Infragravity Wave

Several studies have reported the development of undular bores over fringing coral reefs (e.g, Gallagher, 1976; Nwogu and Demirbilek, 2010) but the importance of this phenomenon for reef hydrodynamics has never been studied. Yet, the transformation of a long wave (e.g., swell or infragravity wave) into an undular bore leads to significant modifications of the wave field. The formation of undulations is for example associated to a significant increase of the leading bore height. Moreover, if the undulations have enough time to develop (i.e. if the reef flat is wide enough), the initial long wave will ultimately split into a series of solitons (e.g., Grue et al., 2008). All this is likely to affect wave run-up. As reeffronted coastlines are particularly vulnerable to flooding, a good understanding of long wave transformation over the reef flat, including their possible transformation into undular bores, is crucial. In this study, we investigate undular bore development over reef-type profiles based on a series of laboratory experiments. More specifically, we aim to characterize the conditions under which undular bores develop, and analyse how their development affect the hydrodynamics at the toe of the reef-lined beach and the resulting wave run-up.

Characteristics of Transforming Waves Breaking Over a Fringing Reef

2019 ◽  
Author(s):  
Fuxian Gong ◽  
Manhar R. Dhanak
Keyword(s):  
Energy Flux ◽  
Wave Breaking ◽  
Reef Flat ◽  
Stokes Equations ◽  
Second Harmonic ◽  
Breaking Waves ◽  
Wave Transformation ◽  
Fundamental Wave ◽  
Fringing Reef ◽  
Wave Shoaling

Abstract Direct numerical simulation (DNS), based on solution of the Navier Stokes equations, is used to study the characteristics of the transformation of monochromatic waves over a simplified fringing reef, including wave shoaling, and wave breaking that occurs under certain circumstances. The reef geometry involves a sloped plane beach extended with a simple submerged horizontal reef flat. The characteristics are studied for several case studies involving a selection of submergence depths on the reef flat and for a range of incident wave conditions, corresponding to nonbreaking, a spilling breaker and a plunging breaker, are considered. The results are compared with those of laboratory experiments (Kouvaras and Dhanak, 2018). Consistent with other studies, generation of harmonics of the fundamental wave frequency is found to accompany the wave transformation over the reef and the process of transfer of energy through wave breaking. The energy flux decreases dramatically in the onshore direction when the waves break. The more severe the wave breaking process, the greater the decrease in energy flux, particularly in the wave shoaling process. Most of the wave energy is carried by the first harmonic throughout its passage over the fringing reef. In nonbreaking waves, the energy gradually transfers from the first harmonic to the second harmonic due to bottom effects in terms of flat wave troughs and secondary waves. The further the distance away from the fore edge of the reef, the larger the percentage of the transmission, resulting in a single dominant harmonic frequency at the end of the wave surfing zone. For breaking waves, the energy carried by the first harmonic gradually decreases in the onshore direction. Energy transmission between harmonics is not as efficient as nonbreaking waves, while wave dissipation is significant in the wave breaking process.

scholarly journals THE RESPONSE OF HARBOR ENVIRONMENTS PROTECTED BY IRREGULAR FRINGING REEF SYSTEMS TO STRONG GRAVITY WAVE FORCING - A CASE STUDY

2018 ◽  
pp. 44
Author(s):  
Assaf Azouri ◽  
Volker Roeber ◽  
Douglas S. Luther
Keyword(s):  
High Resolution ◽  
Numerical Models ◽  
Winter Season ◽  
Water Level Fluctuations ◽  
Wave Transformation ◽  
Fringing Reef ◽  
Wave Forcing ◽  
North Shore ◽  
Transformation Processes

Three high-resolution, dispersive nearshore numerical models (BOSZ - Roeber & Cheung, 2012; FUNWAVE - Shi et al., 2012; XBeach - Roelvink et al., 2009) are compared and contrasted with observations from fringing- reef and harbor environments, in an attempt to test their ability to reproduce the wave transformation processes in a complex Hawaiian reef-system environment forced by highly energetic sea/swell wave conditions. Hale’iwa Harbor, located on Oahu’s North Shore (Figure 1), is a small boat harbor that faces serious operational problems resulting from water level fluctuations and currents during periods of strong swells. These oscillations are predominantly at infragravity periods (rather than swell periods), and, nearly every winter season, their amplitude levels are sufficiently large to trigger significant surges in the harbor. These surges can cause damage to harbor infrastructure and boats, and threaten the safety of mariners who attempt to enter or exit the harbor.

scholarly journals FULLY NONLINEAR BOUSSINESQ-TYPE MODELLING OF INFRAGRAVITY WAVE TRANSFORMATION OVER A LOW-SLOPING BEACH

2012 ◽  
Vol 1 (33) ◽  
pp. 28 ◽  
Author(s):  
Marion Tissier ◽  
Philippe Bonneton ◽  
Gerben Ruessink ◽  
Fabien Marche ◽  
Florent Chazel ◽  
...  
Keyword(s):  
Surf Zone ◽  
Field Studies ◽  
Wave Transformation ◽  
Type Model ◽  
Infragravity Waves ◽  
Fully Nonlinear ◽  
Complex Interactions ◽  
Long Wave ◽  
Sloping Beach ◽  
Infragravity Wave

Recent field studies over low sloping beaches have shown that infragravity waves could dissipate a significant part of their energy in the inner surf zone. This phenomenon and the associated short- and long-wave transformations are not well-understood. In this paper, we assess the ability of the fully nonlinear Boussinesq-type model introduced in Bonneton et al. (2011) to reproduce short and long wave transformation in a case involving a strong infragravity wave dissipation close to the shoreline. This validation study, based on van Dongeren et al. (2008)’s laboratory experiments, suggests that the model is able to predict infragravity wave breaking as well as the complex interactions between short and long waves in the surf zone.

scholarly journals MODELLING WAVE TRANSFORMATION ACROSS A FRINGING REEF USING SWASH

2012 ◽  
Vol 1 (33) ◽  
pp. 26 ◽  
Author(s):  
Marcel Zijlema
Keyword(s):  
Wave Propagation ◽  
Coral Reef ◽  
Wave Breaking ◽  
Flow Model ◽  
Wave Transformation ◽  
Wave Flow ◽  
Infragravity Waves ◽  
Fringing Reef ◽  
Wave Induced ◽  
Steep Slopes

This paper presents the application of the open source non-hydrostatic wave-flow model SWASH to wave propagation over a fringing reef, and the results are discussed and compared with observations obtained from a laboratory experiment subjected to various incident wave conditions. This study focus not only on wave breaking, bottom friction, and wave-induced setup and runup, but also on the generation and propagation of infragravity waves beyond the reef crest. Present simulations demonstrate the overall predictive capabilities of the model for a typical coral reef with steep slopes and extended reef flats.

Wave Transformation on a Fringing Reef System With Spur and Groove Structures

2021 ◽  
Vol 126 (9) ◽  
Author(s):  
César A. Acevedo‐Ramirez ◽  
W. Stephenson ◽  
S. Wakes ◽  
I. Mariño‐Tapia
Keyword(s):  
Wave Transformation ◽  
Fringing Reef ◽  
Reef System

Physical and Numerical Modeling of Irregular Wave Transformation over a Fringing Reef

2016 ◽  
Vol 75 (sp1) ◽  
pp. 922-926
Author(s):  
Sungwon Shin ◽  
Young-Taek Kim ◽  
Jong-In Lee
Keyword(s):  
Numerical Modeling ◽  
Wave Transformation ◽  
Fringing Reef ◽  
Irregular Wave

scholarly journals Experimental and Numerical Studies on Wave Breaking Characteristics over a Fringing Reef under Monochromatic Wave Conditions

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Jong-In Lee ◽  
Sungwon Shin ◽  
Young-Taek Kim
Keyword(s):  
Energy Dissipation ◽  
Wave Breaking ◽  
Model Verification ◽  
Wave Transformation ◽  
Monochromatic Wave ◽  
Layer Model ◽  
Boussinesq Model ◽  
Fringing Reef ◽  
Wave Conditions ◽  
The Cross

Fringing reefs play an important role in protecting the coastal area by inducing wave breaking and wave energy dissipation. However, modeling of wave transformation and energy dissipation on this topography is still difficult due to the unique structure. In the present study, two-dimensional laboratory experiments were conducted to investigate the cross-shore variations of wave transformation, setup, and breaking phenomena over an idealized fringing reef with the 1/40 reef slope and to verify the Boussinesq model under monochromatic wave conditions. One-layer and two-layer model configurations of the Boussinesq model were used to figure out the model capability. Both models predicted well (r2>0.8)the cross-shore variation of the wave heights, crests, troughs, and setups when the nonlinearity is not too high(A0/h0<0.07in this study). However, as the wave nonlinearity and steepness increase, the one-layer model showed problems in prediction and stability due to the error on the vertical profile of fluid velocity. The results in this study revealed that one-layer model is not suitable in the highly nonlinear wave condition over a fringing reef bathymetry. This data set can contribute to the numerical model verification.

The coastal refraction-diffraction wave propagation model

1995 ◽  
Vol 17 (4) ◽  
pp. 6-12
Author(s):  
Nguyen Tien Dat ◽  
Dinh Van Manh ◽  
Nguyen Minh Son
Keyword(s):  
Wave Propagation ◽  
Field Data ◽  
Surf Zone ◽  
Propagation Model ◽  
Wave Transformation ◽  
Diffraction Effect ◽  
Linear Wave ◽  
Diffraction Wave ◽  
Linear Wave Propagation ◽  
Wave Propagation Model

A mathematical model on linear wave propagation toward shore is chosen and corresponding software is built. The wave transformation outside and inside the surf zone is considered including the diffraction effect. The model is tested by laboratory and field data and gave reasonables results.

PHYSICAL INTERPRETATION OF WAVE BREAKING CRITERIA

2017 ◽  
Author(s):  
Sergey Kuznetsov ◽  
Sergey Kuznetsov ◽  
Yana Saprykina ◽  
Yana Saprykina ◽  
Boris Divinskiy ◽  
...  
Keyword(s):  
Nonlinear Wave ◽  
Wave Breaking ◽  
Second Harmonic ◽  
Vertical Axis ◽  
Breaking Waves ◽  
Wave Transformation ◽  
Spectral Structure ◽  
Similarity Parameter ◽  
Nonlinear Harmonics ◽  
The Waves

On the base of experimental data it was revealed that type of wave breaking depends on wave asymmetry against the vertical axis at wave breaking point. The asymmetry of waves is defined by spectral structure of waves: by the ratio between amplitudes of first and second nonlinear harmonics and by phase shift between them. The relative position of nonlinear harmonics is defined by a stage of nonlinear wave transformation and the direction of energy transfer between the first and second harmonics. The value of amplitude of the second nonlinear harmonic in comparing with first harmonic is significantly more in waves, breaking by spilling type, than in waves breaking by plunging type. The waves, breaking by plunging type, have the crest of second harmonic shifted forward to one of the first harmonic, so the waves have "saw-tooth" shape asymmetrical to vertical axis. In the waves, breaking by spilling type, the crests of harmonic coincides and these waves are symmetric against the vertical axis. It was found that limit height of breaking waves in empirical criteria depends on type of wave breaking, spectral peak period and a relation between wave energy of main and second nonlinear wave harmonics. It also depends on surf similarity parameter defining conditions of nonlinear wave transformations above inclined bottom.

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