Local Concentration of Waves Due to Abrupt Alongshore Variation of Nearshore Bathymetry

Ranasinghe, Roshan Suminda; Fukase, Yutaro; Sato, Shinji; Tajima, Yoshimitsu

doi:10.1142/s0578563411002331

Cited by 4 publications

(3 citation statements)

References 6 publications

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“…Small-scale laboratory experiments and simulations were conducted previously (Ranasinghe et al, 2010) to verify the mechanism of wave concentration over abruptly changing bottom topography in alongshore direction, which primarily results due to wave-current interaction (will not be explained in detail in this paper).…”

Section: Resultsmentioning

confidence: 99%

Locally Concentrated Damage at Shimoniikawa Coast, Toyama Bay, Japan Due to Giant Swell Waves

Ranasinghe

Fukase

Sato

et al. 2011

Int. Conf. Coastal. Eng.

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This paper summarizes results of the preliminary research work, which was completed on identifying and assessing the details of locally concentrated damage along the Shimoniikawa coast, Toyama Bay, Japan due to high swell waves (Yorimawari waves, in Japanese), which occurred on 24th February 2008. A comprehensive analysis has been performed on water surface elevations converted from the total water pressure data, which were obtained at Tanaka observation point from 14th February – 29th February 2008 to investigate the strength of these waves. The spectrum analysis showed a perceptible development of long wave components during this event, which was generated by the nonlinear (secondary) interactions of free waves. Several other mechanisms were also found to be in existence, which were responsible for the high wave overtopping and damage due to concentration of waves at some sites along the Shimoniikawa coast. Furthermore, numerical simulations have been performed to verify the wave transformation and concentration of waves at damaged sites using a model developed based on Nwogu (1993) Boussinesq-type equations.

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Section: Resultsmentioning

confidence: 99%

Locally Concentrated Damage at Shimoniikawa Coast, Toyama Bay, Japan Due to Giant Swell Waves

Ranasinghe

Fukase

Sato

et al. 2011

Int. Conf. Coastal. Eng.

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“…In the present study, the wave transformation in nearshore is modelled using a truncated form of Chen (2006) and Nwogu (1993) Boussinesq-type wave equations coupled with one-equation turbulence model (Nowgu, 1996) type) to determine the temporal and spatial evolution of the turbulent kinetic energy produced by wave breaking. Nwogu (1996), Tajima et al (2007), Ranasinghe et al (2009aRanasinghe et al ( , 2011, Siddique et al (2017) and Ranasinghe (2018) followed a similar approach for wave breaking induced energy dissipation over plane seabed slopes and seabeds with submerged structures; however, all used values for mixing length which are specific to the cases they studied. BOUSS-2D, a Boussinesq wave model developed to simulate waves and currents in nearshore regions and harbours by US Army Corps of Engineers (Nwogu & Demirbilek, 2001) too employs a TKE equation for wave breaking induced energy dissipation and recommends a value equal to water wave height for mixing length but with no emphasis on any variation due to bottom configuration or wave period.…”

Section: Introductionmentioning

confidence: 99%

Simulation of breaking waves over different seabed configurations using phase-resolving wave models

Ranasinghe

2021

J. Natn. Sci. Foundation Sri Lanka

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The applicability of two phase-resolving wave models (Boussinesq-type) for simulating wave transformation over seabeds with plane slopes and with submerged structures is further investigated by coupling a turbulent kinetic energy (TKE) equation for wave breaking induced energy dissipation. Previous studies have shown that the models developed using Boussinesq equations with improved nonlinearity and frequency dispersion are capable of simulating wave evolution over mildly sloping beaches at shallow/intermediate water depths but with little emphasis on changes to bottom configurations. In this study, a published set of data is used to calibrate two phaseresolving wave models developed extending an improved form of the Boussinesq equations to include steep localised bottom slopes and wave breaking induced energy dissipation. The first model is limited to simulating wave transformation over impermeable beds but the second model is developed to incorporate porous beds. Porous damping is introduced in the second model by coupling the governing equations with a nonlinear Darcy-Forchheimer equation. The calibrated models with appropriate values for relevant model parameters are found to reproduce wave height, mean water level distributions across the surf zone for different wave conditions and bottom configurations with a high-level of accuracy in 1-dimensional horizontal (1DH) wave propagation. The results obtained from this study are vital in validating a 2-dimensional horizontal (2DH) wave-current model.

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“…Tajima and Sato (2010) carried out the laboratory experiments on the two dimensional basin and investigated how wave heights are locally concentrated when group waves with slowly varying envelopes were incident on the bathymetry where two bottom plane panels with different cross-shore slopes were attached with each other in the middle of the basin and a straight vertical seawall was placed along the shore. Ranasinghe et al (2011) carried out the similar experiments to those of Tajima and Sato (2010) and also tested the applicability of Boussinesq-type non-linear dispersive wave model for predictions of such wave concentrations.…”

Section: Introductionmentioning

confidence: 99%

Image-Based Field Observation of Infragravity Waves Along the Swash Zone

Tajima

2014

Int. Conf. Coastal. Eng.

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This study develops an image-based monitoring techniques for observations of surf zone hydrodynamics especially focusing on evolution and propagations of infragravity waves along the coast. Laboratory experiment was first performed to investigate the relationship between image-captured shoreline fluctuations and recorded actual water surface fluctuations inside the surf zone. Frequency components of infragravity waves were extracted respectively from observed shoreline changes and recorded water surface fluctuations. Both components showed good agreement in terms of their alongshore distributions of phases and amplitudes. The same image-based technique was applied to the field, the Seisho coast when the typhoon 1112 approached the site and extracted infragravity wave components were found to be consistent with offshore wave data and showed characteristics of edge waves.

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Local Concentration of Waves Due to Abrupt Alongshore Variation of Nearshore Bathymetry

Cited by 4 publications

References 6 publications

Locally Concentrated Damage at Shimoniikawa Coast, Toyama Bay, Japan Due to Giant Swell Waves

Locally Concentrated Damage at Shimoniikawa Coast, Toyama Bay, Japan Due to Giant Swell Waves

Simulation of breaking waves over different seabed configurations using phase-resolving wave models

Image-Based Field Observation of Infragravity Waves Along the Swash Zone

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