Topic
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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TL;DR: In this article, a practical method has been formulated to predict the second order wave loads on large offshore structures, including cylinders and square caissons, and the theoretical predictions have been compared with the experimental measurements and the comparison shows good agreement.
7 citations
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TL;DR: In this paper, a perforated vertical wall caisson has been tested with both irregular and regular waves, reproducing mild wave conditions and design wave conditions, and the effect of the wave obliquity and of the short crestedness on the reflection coefficient is discussed.
Abstract: This paper presents new tests on a perforated vertical wall caisson. The tests aim at evaluating the reduction of the reflection coefficient caused by different perforations. The reflection coefficient is estimated using the novel nonlinear methods proposed by Lykke Andersen et al. (2017) and Eldrup and Lykke Andersen (2019). The structure under investigation is, at prototype scale, 21.50 m high, 35.55 m long and 13.90 m wide, divided into 3 rows of 8 cells. The caisson has a recurved ‘nose’ and air vents on the parapet wall. An identical plain wall caisson without absorbing chambers is also tested for comparison. Two-dimensional laboratory tests have been carried out at Department of Engineering of Roma Tre University with both irregular and regular waves, reproducing mild wave conditions and design wave conditions. Two water levels have been used, reproducing the mean water level and a set-up condition of +0.5 m. Four structural layouts are tested in order to study various perforation types. Furthermore, the effect of the wave obliquity and of the short crestedness on the reflection coefficient is discussed using some 3D laboratory data obtained back in the 1995 but not published before.
7 citations
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30 Oct 2014TL;DR: In this article, a wave impact generator is used on a prototype dike in the field and can generate wave impacts on a slope to quantify the residual strength of grass under wave attack and implement this in design and assessment tools.
Abstract: Outer slopes of grass dikes under wave attack are likely to have residual strength, which is the strength after initial damage has occurred. This strength is not included in current design and assessment tools. To quantify the residual strength of grass under wave attack and implement this in design and assessment tools, a large research program is initiated within the Dutch WTI 2017 project. This project is financed by Rijkswaterstaat. In this research program an integrated approach, a combined use of a so-called wave impact generator and large-scale wave flume tests in the Delta Flume is applied. This approach contributes to a future strength model which includes residual strength of the outer slope of grass dikes under wave loads, primarily along large rivers.
Grass cannot be scaled properly and many variations exist in grass covers (clay quality, grass quality, transitional structures, objects in or on the dike, et cetera). For this reason, testing with traditional physical wave flume models would lead to unacceptable high costs since many tests are required. Therefore, a wave impact generator is developed (Van Steeg et al, 2014). This machine can be placed easily on a prototype dike in the field and can generate wave impacts on a slope. During testing, the machine is continuously filled by a pump. By opening a pre-programmed valve irregularly, a mass of water is relieved leading to an impact that resembles impacts caused by natural waves.
The developed wave impact generator is applied in an extensive measurement campaign on several grass dikes in the Netherlands. Variations of the thirteen different test sections were on grass and clay quality but also transition structures and objects (pole, open concrete blocks allowing grass growth, stairs). This leads to valuable erosion patterns as function of geometric properties of the outer slope of the dike. The hydraulic load during all tests was the same.
Although wave run-up levels and wave impact pressures due to the wave impact generator are close to natural waves, there is a need to calibrate the results obtained with the wave impact generator. Therefore, large scale physical model tests in the Delta Flume, with a selection of the dikes tested with the wave impact generator, are performed. Blocks of 2 m x 2 m x 0.8 m were taken from dikes and were transported to the Delta Flume. In this flume (L x B x D = 235 m x 5 m x 7 m), waves can be generated up to a significant wave height of Hs = 1.6 m.
Erosion patterns obtained with the wave impact generator and erosion patterns obtained in the large scale flume were compared. Based on this comparison and based on impact pressure analysis it is concluded that the wave impact generator represents a load which is equivalent to a significant wave height of Hs = 0.6 – 0.7 m, a wave steepness of sop 4-5%.
The integrated use of the wave impact generator and a large-scale wave flume led to valuable data. This data will be used to improve the strength model for outer slopes of grass dikes under wave attack.
7 citations
01 Jan 2007
TL;DR: In this article, a set of representative waves is derived for the coast adjacent to the Ria de Aveiro, such that it is morphologically equivalent to the complete wave regime.
Abstract: PLECHA, S., SANCHO, F., SILVA, P. and DIAS, J.M., 2007. Representative waves for morphological simulations. Journal of Coastal Research, SI 50 (Proceedings of the 9th International Coastal Symposium), 995 – 999. Gold Coast, Australia, ISSN 0749.0208 In the present study, a set of representative waves is derived for the coast adjacent to the Ria de Aveiro, such that it is morphologically equivalent to the complete wave regime. Different schematising methodologies are presented, based on the principles of conservation of wave energy and equivalent longshore sediment transport capacity over the beach profile. Firstly, the sediment transport capacities due to the whole set of waves is computed and then various sets of representative waves are proposed based on the principles above. The most suitable set is selected by taking into account the dominant sediment transport processes at the selected site. The representative waves can be used to significantly reduce computational time in morphological models, by reducing the number of different sea states that characterise the annual wave climate. This simplified nearshore wave regime shall provide the wave effects into the sediment transport formulae and the hydrodynamical model.
7 citations
01 Jan 2009
TL;DR: A diverse series of research projects have taken place or are underway at the NEES Tsunami Research Facility at Oregon State University as discussed by the authors, including simulation of the processes and effects of tsunamis generated by sub-aerial and submarine landslides, model comparisons of tsunami wave effects on bottom profiles and scouring (NEESR, Princeton University), model comparison of wave induced motions on rigid and free bodies (Shared-Use, Cornell), numerical model simulations and testing of breaking waves and inundation over topography, structural testing and development of standards for tsunami engineering and design
Abstract: A diverse series of research projects have taken place or are underway at the NEES Tsunami Research Facility at Oregon State University. Projects range from the simulation of the processes and effects of tsunamis generated by sub-aerial and submarine landslides (NEESR, Georgia Tech.), model comparisons of tsunami wave effects on bottom profiles and scouring (NEESR, Princeton University), model comparisons of wave induced motions on rigid and free bodies (Shared-Use, Cornell), numerical model simulations and testing of breaking waves and inundation over topography (NEESR, TAMU), structural testing and development of standards for tsunami engineering and design (NEESR, University of Hawaii), and wave loads on coastal bridge structures (non-NEES), to upgrading the two-dimensional wave generator of the Large Wave Flume. A NEESR payload project (Colorado State University) was undertaken that seeks to improve the understanding of the stresses from wave loading and run-up on residential structures. Advanced computational tools for coupling fluid-structure interaction including turbulence, contact and impact are being developed to assist with the design of experiments and complement parametric studies. These projects will contribute towards understanding the physical processes that occur during earthquake generated tsunamis including structural stress, debris flow and scour, inundation and overland flow, and landslide generated tsunamis. Analytical and numerical model development and comparisons with the experimental results give engineers additional predictive tools to assist in the development of robust structures as well as identification of hazard zones and formulation of hazard plans.
7 citations