Wave flume

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

Dynamics of Wave Setup over a Steeply Sloping Fringing Reef

Abstract: High-resolution observations from a 55-m-long wave flume were used to investigate the dynamics of wave setup over a steeply sloping reef profile with a bathymetry representative of many fringing coral reefs. The 16 runs incorporating a wide range of offshore wave conditions and still water levels were conducted using a 1:36 scaled fringing reef, with a 1:5 slope reef leading to a wide and shallow reef flat. Wave setdown and setup observations measured at 17 locations across the fringing reef were compared with a theoretical balance between the local cross-shore pressure and wave radiation stress gradients. This study found that when radiation stress gradients were calculated from observations of the radiation stress derived from linear wave theory, both wave setdown and setup were underpredicted for the majority of wave and water level conditions tested. These underpredictions were most pronounced for cases with larger wave heights and lower still water levels (i.e., cases with the greatest setdow...

On the synthesis of realistic Sea States in a laboratory flume

Abstract: Background report on how to make realistic waves in laboratory flumes, including the method of splitting wave signals into incoming and reflecting waves

Stem breakage of salt marsh vegetation under wave forcing: A field and model study

Abstract: One of the services provided by coastal ecosystems is wave attenuation by vegetation, and subsequent reduction of wave loads on flood defense structures. Therefore, stability of vegetation under wave forcing is an important factor to consider. This paper presents a model which determines the wave load that plant stems can withstand before they break or fold. This occurs when wave-induced bending stresses exceed the flexural strength of stems. Flexural strength was determined by means of three-point-bending tests, which were carried out for two common salt marsh species: Spartina anglica (common cord-grass) and Scirpus maritimus (sea club-rush), at different stages in the seasonal cycle. Plant stability is expressed in terms of a critical orbital velocity, which combines factors that contribute to stability: high flexural strength, large stem diameter, low vegetation height, high flexibility and a low drag coefficient. In order to include stem breakage in the computation of wave attenuation by vegetation, the stem breakage model was implemented in a wave energy balance. A model parameter was calibrated so that the predicted stem breakage corresponded with the wave-induced loss of biomass that occurred in the field. The stability of Spartina is significantly higher than that of Scirpus, because of its higher strength, shorter stems, and greater flexibility. The model is validated by applying wave flume tests of Elymus athericus (sea couch), which produced reasonable results with regards to the threshold of folding and overall stem breakage percentage, despite the high flexibility of this species. Application of the stem breakage model will lead to a more realistic assessment of the role of vegetation for coastal protection.

Generation of internal solitary wave by gravity collapse

Abstract: Laboratory experiments were conducted to investigate the generation of an internal solitary wave (ISW) in a two-layer free surface fluid system in wave flume (12 m · 0.5 m · 0.7 m), which included wave channel and compartment. There is filled with stratified twolayer fluid system in the channel and small compartment, respectively. These two regions in the wave flume are separated by a movable vertical gate at one end of the flume for generating the ISW (internal solitary wave). An ISW generation is thus caused by gravity collapse upon raising the vertical gate. Given positive potential energies, an elevation-type ISW is followed by an anticlockwise overturning motion at the interface; on the other hand, an ISW of depression-type was generated by clockwise motion. This paper presented physical properties related to wave generation in a stratified fluid in laboratory. In the wave flume, the stable wave propagation, either elevation-type or depression-type ISW, is influenced by environmental condition. An ISW of depression transferred into unstable fluctuation instead of soliton feature whilst the upper layer thickness is greater than the lower layer thickness. Similarly, an ISW of elevation reduces its wave amplitude and causes trailing oscillation followed with the leading wave.