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Wave flume

About: Wave flume is a research topic. Over the lifetime, 1627 publications have been published within this topic receiving 23335 citations.


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Journal ArticleDOI
01 Dec 2010
TL;DR: The analysis of wave absorption and generation algorithms that were latter applied in the new wave basin constructed at the University of São Paulo (USP), as part of the Numerical Offshore Tank (TPN) Laboratory is presented.
Abstract: This paper presents the analysis of wave absorption and generation algorithms that were latter applied in the new wave basin constructed at the University of Sao Paulo (USP), as part of the Numerical Offshore Tank (TPN) Laboratory. These algorithms calculate the motions of the wave makers both to generate and absorb the required wave field by taking into account the layout of the flaps and the limits of wave generation. In order to study different aspects of the implementation, the performance of a prototype device composed of 4 flaps was evaluated in a 2D wave flume, prior to the assembly of the complete system at the TPN wave basin. The generation algorithms are based on the summation of wave components (frequencies and directions) obtained from the required directional wave spectrum. The transfer function that relates the flap motion to the generated wave is considered. Absorption tests were conducted using two different algorithms: a frequency domain method based on Maeda et al. (2004), in which the controlled variable is the motor velocity, and the time domain algorithm proposed by Schaffer (2001). The latter is based on a digital filter and the position of the flap is the variable to be controlled. Both algorithms require hydrodynamic feedback based on the measurement of the surface elevation at each flap. The first algorithm needs an extensive test procedure to calibrate its control parameters, while the second one, after optimizing the digital filter, should be ready to use. Both algorithms presented similar results with reflection coefficients smaller than 10.7% for regular waves with frequencies ranging from 0.5 to 1.5 Hz.
Book ChapterDOI
01 Jan 2021
TL;DR: In this paper, numerical simulations are carried out using one-dimensional Boussinesq wave model for submerged (i) broad dykes, (ii) narrow dykes and (iii) semi-circular breakwater and (iv) rigid vegetation.
Abstract: The wave–structure interaction besides hydrodynamics over natural and submerged breakwaters is an empirical process due to the complex flow process A better understanding of the wave transmission through natural and artificial submerged breakwaters is vital in the field of coastal conservation The studies investigating transmission coefficient (KT), in general using phase averaging approach, in particular are limited In this study, numerical simulations are carried out using one-dimensional Boussinesq wave model for submerged (i) broad dykes, (ii) narrow dykes, (iii) semi-circular breakwater and (iv) rigid vegetation The validation of the model is done with a series of experimental observations carried out in two-dimensional wave flume for each breakwater KT decreases with increasing wave steepness, relative crest width, relative water depth, relative crest free board for all kinds of breakwater configurations In particular, KT was observed to be more for broad dykes and less for rigid vegetation Model results were compared using physical model tests, and also with numerical and empirical models Furthermore, wave transmission coefficients obtained from the laboratory model experimental investigation are in good agreement with the numerical simulations Phase averaging approach gives more insight into the physical description of the wave–structure interaction over and around submerged breakwaters where limited experimental data is available
Journal ArticleDOI
TL;DR: A numerical wave flume (CADMAS-SURF/2D) developed on the basis of NASA-VOF technique is used to simulate interactions between waves and maritime structures in order to verify its feasibility to maritime structure designs as discussed by the authors.
Abstract: A numerical wave flume (CADMAS-SURF/2D) developed on the basis of NASA-VOF technique is used to simulate interactions between waves and maritime structures in order to verify its feasibility to maritime structure designs. Examinations and comparisons of the calculated results of wave impacts on typical maritime structures, such as caisson-type and composite breakwaters, with experimental data indicate that the numerical wave flume can be an effective computer aided design tool for the designs of coastal protection structures.
Dissertation
01 Jan 2015
TL;DR: In this paper, the authors provide an empirical model which describes the development of wave dissipation over a salt marsh meadow under storm surge conditions, which can be used as a quantitative basis for decisions concerning flood protection measurements.
Abstract: With an increasing awareness of ecological value and rising sea levels the use of vegetation in flood protection becomes widely accepted. To evaluate and quantify the benefits of a salt marsh meadow for flood protection, knowledge about the evolution of wave dissipation over the marsh is necessary. The objective of this research is to provide an empirical model which describes the development of wave dissipation over a salt marsh meadow under storm surge conditions. A method for the analysis of the data and the preparation of the model is also provided. The data is gathered in a large wave flume (Grosser Wellenkanal) in Hannover. A vegetated section of 39.44 meter length was built up of field excavated pieces of salt marsh turf. Elymus, Atriplex, and Puccinnellia are used as vegetation to represent a southern North Sea mars community. The data is obtained using 5 groups of 3 pressure transmitters and one group of 2 pressure transmitters. The pressure data is processed into surface elevation using linear wave theory. The surface elevation is calculated in frequency domain. It was necessary to use a low pass filter as the model was not appropriate for the higher frequencies. A high pass filter is applied to remove the offset of several spectrums. The method is limited as the pressure transmitters could not measure a signal of a wave with an amplitude of 0.1 meter. Several nonlinear tests were also excluded from the analysis. Nonlinear waves typically show more amplitude peaks in frequency domain. These peaks are determining for the wave shape in time domain. Some of the wave conditions showed peaks beyond the low pass filter. Both an analysis of the evolution of wave height dissipation as well as an analysis of the wave energy flux dissipation is considered. A time interval with no influence of reflected waves is used in which the mean wave height is calculated. As theory states that wave dissipation shows an exponential behaviour, exponential functions are fitted to the mean wave height. The average wave energy flux is calculated using the mean wave height. Exponential functions are also fitted to this average wave energy flux plotted against the distance into the marsh. Empirical functions are derived on the basis of the parameters of the fitted functions. Both approaches showed low coefficients of variation but the approach on the basis of wave height dissipation seemed most accurate. Both approaches are presented as a function of the initial value and a decrease parameter. As a suggestion, the decrease parameter is presented as a function of the water depth. A comparison of the empirical functions with corresponding data from tests with mowed vegetation shows a significant faster process of dissipation for the derived empirical functions. The salt marsh has a significant influence on wave height dissipation. This conclusion is supported by Moller et al. (2014) as they concluded that up 60% of wave height attenuation can be attributed to the vegetation. They used the same data for this conclusion. The evolution of wave dissipation shows a process that can be described as a function of the length of the salt marsh. This empirical relationship can be used as a quantitative basis for decisions concerning flood protection measurements. The present research showed a significant faster process of energy dissipation over a lower water depth. Recommendations include a further research to the dependency of the decrease parameter on other parameters than the water depth. Further research to the influence of the water depth on the dissipation process seems also necessary as the present research is only based on two water depths. Further research with the use of a longer salt marsh will benefit the quality of the results as the present data only seemed to describe the first section of the process of wave dissipation.
Journal ArticleDOI
TL;DR: In this paper, the performance of a two-bladed Savonius turbine operating under three new strategies aiming to enhance the turbine's capability of wave energy power generation was investigated.

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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202331
202284
202165
202069
201964
201859