Motion threshold of coarse particles under regular shoaling waves

Threshold of motion of coarse particles under regular shoaling waves is studied. Experiments were performed to investigate the effects of bed fluid acceleration on coarse particle stability. By varying wave height, wave period and water depth combinations of similar peak orbital velocities and weak to strong intra-wave accelerations were created...

Coarse particles' threshold of motion under shoaling waves

The threshold of motion of coarse particles under regular shoaling waves is studied. Experiments are performed to investigate the effects of bed fluid acceleration on coarse particle stability. By varying wave height, wave period and water depth, combinations of similar peak orbital velocities and weak to strong intra-wave accelerations were...

On the scaling of sediment transport in the nearshore

Scale relations are necessary to choose proper sediment for physical models. The use of lightweight artificial sediment makes it possible to preserve the Reynolds number, Shields number and relative settling velocity altogether. There is also the possibility to preserve the Shields number in combination with the Dean number which would be more...

Surfing waves generated by a hull

In this paper a new wave pool concept is presented using ship hulls as wave generators. To evaluate the potential of such a concept a towing tank experiment is conducted to investigate ship wave generation in a confined space. In the towing tank experiment various hull sizes and velocities are examined to maximize the generated wave height. The...

What determines nearshore sandbar response?

Nearshore sandbars appear with various patterns which may change over time. From observations, these changes seem to be related to changes in hydrodynamic conditions, although observed length scales could not be related directly to occurring wave conditions. The current work investigated the role of both the concurrent and previous hydrodynamics...

Wave boundary layer hydrodynamics during onshore bar migration

To study onshore bar migration and the accompanying intra-wave sediment transport a wave flume experiment was conducted. The wave flume had a rigid bottom with a single bar profile. The focus of the experiment was to measure the hydrodynamics in the wave bottom boundary layer. The results show that the skewness of bottom stress is not only...

On the initiation of nearshore morphological rhythmicity

Nearshore rhythmicity is often initiated in the period just after a storm where the subtidal bar is turned alongshore uniform. The initiation time as well as the length scales of the created rhythmicity varies from one storm period to another. Here we show that the post-storm wave conditions are related to the initiation of the morphological...

Vortex tubes in the wave bottom boundary layer

The cause of sediment suspension events during flow reversal under waves in the nearshore is not well understood. Vortex tubes and horizontal pressure gradients have been suggested to be the cause of the suspension events. A medium sized wave flume experiment has been conducted to give insight in the hydrodynamics of the wave bottom boundary...

Morphological developments after a beach and shoreface nourishment at Vlugtenburg beach

Typically a beach is out of equilibrium after a nourishment is installed. To observe how a nourished beach behaves on the timescale of storms a monitoring campaign was set up at Vlugtenburg beach after a nourishment in the spring of 2009. Here we show a sediment budget analysis of the first 2.5 years for a coastal domain spanning 1750 m...

Alongshore topographic variability at a nourished beach

The present paper examines the generation and inter-annual evolution of alongshore variability in topography measured after the implementation of a sand nourishment. The magnitude of the topographic variability is quantified using 3.5 years of monthly survey data. The emergence and temporal change in alongshore morphological variability is...

Response in the mekong deltaic coast to its changing sediment sources and sinks

The coastal zone of Mekong delta is suffering under intense pressures from climate change as well as human intervention. Currently, the coastline evolution of Mekong delta is a complex combination of impacts due to (1) relative sea level rise i.e. the sum of eustatic sea level rise, natural and human induced subsidence (2) sediment transport...