Showing papers on "Wave flume published in 1978"
TL;DR: In this article, the quantities of sediment moving as bed load in oscillatory flow over a flat bed were measured with an oscillating tray in still water but some were carried out in a wave flume.
Abstract: Measurements have been made of the quantities of sediment moving as bed load in oscillatory flow over a flat bed. Most of the measurements were made with an oscillating tray in still water but some were carried out in a wave flume. There is good agreement between the two sets of results. For sand and gravel the mean sediment transport rate is observed to vary during the course of the cycle like the fourth power of the velocity of oscillation but with a slight phase lead. For nylon pellets, however, the transport curve is not quite symmetrical about its maximum. Measurements were also made of the random fluctuations in transport rate and these are compared with Abou-Seida's theoretical model. An empirical relationship is derived for the sediment transport rate.
91 citations
TL;DR: In this article, the authors consider the evolution of a long-wave initial data in water of uniform depth and determine explicit criteria for their applicability for the leading wave and the trailing oscillations of the evolving wave train.
Abstract: Model equations which describe the evolution of long-wave initial data in water of uniform depth are tested to determine explicit criteria for their applicability. We consider linear and nonlinear, dispersive and non-dispersive equations. Separate criteria emerge for the leading wave and trailing oscillations of the evolving wave train. The evolution of the leading wave depends on two parameters: the volume (non-dimensional) of the initial data and an Ursell number based on the amplitude and length of the initial data. The magnitudes of these two parameters determine the appropriate model equation and its time of validity. For the trailing oscillatory waves, a local Ursell number based on the amplitude of the initial data and the local wavelength determines the appropriate model equation. Finally, these modelling criteria are applied to the problem of tsunami propagation. Asymptotic ( t → ∞) linear dispersive theory does not appear to be applicable for describing the leading wave of tsunamis. If the length of the initial wave is approximately 100 miles, the leading wave is described by a linear non-dispersive model from the source region until shoaling occurs near the coastline. For smaller lengths (∼ 40 miles) a linear dispersive (but not asymptotic) model is applicable. The longer-period oscillatory waves following the leading wave, which can induce harbour resonance, apparently require a nonlinear dispersive model.
60 citations
TL;DR: In this paper, the importance of the succession of waves to the impact on coastal structures, run-up/down on permeable and impermeable slopes and stability of dolos armour were investigated in model tests by using three different wave patterns.
37 citations
Book•
01 Jun 1978
TL;DR: In this paper, the wave reflection from a movable bed as it adjusted to the impinging waves was the primary source of wave height variability in 10 experiments in 6-and 10-foot-wide wave tanks.
Abstract: : Variation in wave reflection from a movable bed as it adjusted to the impinging waves was the primary source of wave height variability in 10 experiments in 6- and 10-foot-wide wave tanks. Re-reflection of waves from the wave generator, secondary waves, transverse waves, and cross waves also contributed to the wave height variability. Laboratory effects, caused by differences in initial profile slope, initial test length (distance between the wave generator and the initial shoreline), tank width, and water temperature, affected the profile development and the wave height variability. Initial profile slope and initial test length should be kept constant to assure test repeatability in movable-bed experiments. The wavelength-to-tank width ratio should be greater than or equal to 3 to assure two dimensionality of profile development, but two-dimensional profiles may not be realistic replications of three-dimensional profiles.
2 citations