Wave flume

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

A coastal area morphodynamics model

Abstract: A coastal area morphodynamics model was developed which is capable of modelling both short-term and long-term bathymetric changes in coastal areas. The model is composed of three main modules: wave transformation module, hydrodynamic module and sediment transport and morphology module. The three main modules run simultaneously where the waves and coastal currents information are passed to the sediment transport module, which calculates the sediment transport fluxes and the corresponding bathymetric changes. The model's output is linked through dynamic plotting libraries, which produces contour plots, vector plots and animation files for the waves, currents, sediment transport fluxes and bathymetry. The model's output compares very well with other commercial models for the case of an offshore breakwater over a sloping beach.

Internal architecture and evolution of bioclastic beach ridges in a megatidal chenier plain: Field data and wave flume experiment

Abstract: Beach ridges in macrotidal environments experience strong multi-annual to multi-decennial fluctuations of tidal inundation. The duration of tide flooding directly controls the duration of sediment reworking by waves, and thus the ridge dynamics. Flume modelling was used to investigate the impact of low-frequency tidal cycles on beach ridge evolution and internal architecture. The experiment was performed using natural bioclastic sediment, constant wave parameters and low-frequency variations of the mean water level. The morphological response of the beach ridge to water level fluctuations and the preservation of sedimentary structures were monitored by using side-view and plan-view photographs. Results were compared with the internal architecture of modern bioclastic beach ridges in a macrotidal chenier plain (Mont St. Michel Bay, France) surveyed with ground-penetrating radar. The experimentally obtained morphologies and internal structures matched those observed in the field, and the three ridge development stages identified in ground-penetrating radar profiles (early transgressive, late transgressive and progradational) were modelled successfully. Flume experiments indicate that flat bioclastic shapes play a key role in sediment sorting in the breaker zone, and in sediment layering in the beach and washover fans. Water level controls washover geometry, beach ridge evolution and internal structure. Low water levels allow beach ridge stabilization and sediment accumulation lower on tidal flats. During subsequent water level rise, accumulated sediment becomes available for deposition of new washover units and for bayward extension of the beach ridges. In the field, low-frequency water level fluctuations are related to the 4·4 year and 18·6 year tidal cycles. Experimental results suggest that these cycles may represent the underlying factor in the evolution of the macrotidal chenier coast at the multi-decadal to centennial time scale.

Impulse wave run-over: experimental benchmark study for numerical modelling

Abstract: This research intends to provide a detailed data basis for numerical modelling of impulse waves. Three tests are described involving a rectangular wave channel, in which a trapezoidal ‘breakwater’ was inserted to study wave run-over. In addition, a reference test is also described, in which the breakwater was removed. Two-dimensional impulse waves were generated by means of subaerial granular slides accelerated by a pneumatic landslide generator into the water body. Wave propagation and run-over over the artificial breakwater are documented by a set of high-quality photographs. Water surface profiles were recorded using capacitance wave gages upstream and downstream of the breakwater, and velocity vector fields were determined for the run-over zone by means of Particle Image Velocimetry. The measurements are compared with predictive formulae for wave features and wave non-linearity. The present data set involves both simple channel topography and wave features to allow for numerical simulations under basic laboratory conditions.

Entrainment and transport of fine sand by combined waves and current: an experimental study

Abstract: Experiments have been performed in a large wave flume in order to measure sediment transport rate of fine sand under combined regular waves and current. Instantaneous velocities and concentrations are measured using ultrasonic velocimeters and optical turbidity probes. Suspended transport rates, as obtained from vertical integration of measured fluxes, are decomposed into a mean current and an oscillatory wave components. Under waves only, the wave contribution is in the direction of wave propagation. Under combined waves and current, the wave contribution is found to systematically oppose the direction of superimposed mean current.

Secondary waves in coastal zone: physical mechanisms of formation and possible application for coastal protection

Abstract: The formation of secondary wave in a coastal zone was investigated on the base of field, laboratory and numerical experiments. It was found that formation of secondary waves is essentially part of weakly nonlinear-dispersive wave transformation and determined by a periodic exchange of energy between the first and second harmonics. The formation of secondary waves depends on a stage of wave transformation and defined by amplitude of secondary harmonic and by phase shift between first and second harmonics. On the base of numerical modeling and laboratory experiments an idea of combination of underwater structures with floating breakwater is investigated. Waves propagating above submerged bar generate secondary waves that decrease the mean period of waves. Each additional bar reinforces and stabilizes this effect. Behind the bars the floating breakwater can be applied, because it suppresses successfully only short waves. Advantages and disadvantages of this idea are discussed.