Group bounded long waves in physical models

Barthel, Volker; Mansard, E.P.D.; Sand, Stig E.; Vis, F.C.

doi:10.1016/0029-8018(83)90012-4

Cited by 76 publications

(32 citation statements)

References 2 publications

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“…Full wave generation theory correct to second order, for normally propagating waves and applicable to both piston and hinged wave-makers, was derived by Schäffer (1996), who extended earlier analysis by Barthel et al (1983). Schäffer's theory aims to suppress generation of second-order spurious free waves, also known as parasitic or error waves, which are unintentionally generated when linear paddle signals are used.…”

Section: Laboratory Wave Generationmentioning

confidence: 99%

Importance of second-order wave generation for focused wave group run-up and overtopping

Orszaghova

Taylor

Borthwick

et al. 2014

Coastal Engineering

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Focused wave groups offer a means for coastal engineers to determine extreme run-up and overtopping events. Numerical predictions and laboratory measurements are presented for NewWave-type focused wave groups generated by a piston-type paddle generator, and interacting with a plane beach and a seawall in a wave basin. The numerical wave tank is based on the Boussinesq equations for non-breaking waves, and the non-linear shallow water equations for broken waves. Good agreement is achieved between the numerical predictions and laboratory measurements of free surface elevation, run-up distances and overtopping volumes for the test cases driven by linear paddle signals. Errors in run-up distance and overtopping volume are then assessed by repeating the test cases using second-order accurate wave generation signals. Focused wave groups generated using first-order wave-maker theory are found to be substantially contaminated by a preceding long error wave, resulting in erroneously enhanced run-up distances and overtopping volumes. Thus, the use of secondorder wave-maker theory for wave group run-up and overtopping experiments is instead recommended.

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Section: Laboratory Wave Generationmentioning

confidence: 99%

Importance of second-order wave generation for focused wave group run-up and overtopping

Orszaghova

Taylor

Borthwick

et al. 2014

Coastal Engineering

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“…The wave generation is based on the second-order waves so that the parasitic waves can be eliminated (e.g. Ottesen Hansen et al 1980;Barthel et al, 1983). A weakly-reflective boundary is applied at the wave boundary, and the Sommerfeld radiation condition is applied at the end of the numerical domain, in order to minimize the effect of the reflection.…”

Section: In Situ Measurement Setupmentioning

confidence: 99%

“…However, still numerical models do not always represent wave transformation processes accurately, especially in shallow foreshores: free long waves occur since the group bounded waves (e.g. Ottesen-Hansen et al, 1980;Barthel et al, 1983) in the wave train in the offshore are released in the shallow zone through wave breaking and wave-wave interactions. For example spectral wave models cannot reproduce the free long waves since frequency shift due to those phenomena in the breaking zone cannot be modeled properly.…”

Section: Introductionmentioning

confidence: 99%

Two-Dimensional Wave Overtopping Calculation Over a Dike in Shallow Foreshore by Swash

Suzuki

Altomare

Verwaest

et al. 2014

Int. Conf. Coastal. Eng.

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In this paper, a numerical wave-flow model SWASH, based on non-linear shallow water equation with nonhydrostatic pressure, is applied to the estimation of wave overtopping over a dike in shallow foreshores. First sensitivity analysis is conducted to see the influence of wave generation, grid size, time window and bottom friction by one-dimensional calculations. After that the SWASH model is validated by comparing results from field measurements in Petten dike in the Netherlands. Due to the stability of the computation, the desired calculation could not be achieved, but an alternative way to calculate wave overtopping including two-dimensional effects is proposed.

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“…Hansen (1978), Sand (1982), Barthel et al (1983), Sand and Mansard (1986a, b), Mansard (1991), Mansard et al (1987), Schaffer (1993), Stansberg (2006), Zaman and Mak (2007), Zaman et al (2010), Spinneken and Swan (2009) are a few who described the methods to curtailing these unavoidable free waves from the resulting surface elevations in the wave basin.…”

Section: Introductionmentioning

confidence: 99%

Spurious Waves During Generation of Multi-Chromatic Waves in the Wave Tank in Shallow Water

Zaman

Peng

Baddour

et al. 2011

Volume 6: Ocean Engineering

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Accurate generation of the primary waves and the reproduction of the group-induced second-order low and high frequency waves have been considered essential for physical i.e. model test in the laboratory. In the laboratory when multi-chromatic primary waves are generated the required bounded waves will be generated naturally at the difference frequencies. In addition to that several unwanted free waves are also generated. The free waves, having the same frequencies of the bounded waves are reproduced due to mismatch of the boundary conditions at the wave paddle. The other two types of free waves are due to the wave paddle displacement and the local disturbances. We carried out physical experiments to identify the second order spurious waves in shallow water in the Offshore Engineering Basin (OEB) at the Institute for Ocean Technology (IOT) of National Research Council (NRC) Canada. In the basin water depths in the range of 0.4m to 0.6m are used for the experiments. The peak wave periods also have varied from 1.133s to 2.145s. In the experiments multi-chromatic waves are used. The drive signals of the wave-makers are generated using first-order and second-order wave generation techniques. Total 14 wave probes are used to capture the data in the wave tank. A NRC-IOT code is used to isolate the primary waves, the bounded waves and the unwanted free waves from the measured data at each wave probe. The measured data are analyzed in this paper to illustrate the differences in the waves generated by two different generation techniques. KEYWORDPhysical experiments, multi-chromatic shallow water waves, second order waves, Bounded waves, second-order spurious waves, data comparisons.

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Group bounded long waves in physical models

Cited by 76 publications

References 2 publications

Importance of second-order wave generation for focused wave group run-up and overtopping

Importance of second-order wave generation for focused wave group run-up and overtopping

Two-Dimensional Wave Overtopping Calculation Over a Dike in Shallow Foreshore by Swash

Spurious Waves During Generation of Multi-Chromatic Waves in the Wave Tank in Shallow Water

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