Bed behaviour and sand concentration under oscillatory water motion

Dimensies van beddingvormen onder permanente stromingsomstandigheden bij hoog sedimenttransport

Turbulence measurements above artificial dunes

Bedforms, near-bed sediment concentrations and sedimenttransport in simulated regular wave conditions: Experimental study in the large oscillating water tunnel of Delft Hydraulics

Experiments with graded sediments in a straight flume: Report on experimental investigations

A literature review on sand transport under oscillatory flow conditions in the rippled-bed regime

Experimental results are very important to understand the complex nature of sand transport. They give insight in the relevant processes and can be used to validate model concepts. Most of the laboratory experiments on wave-related transport processes are carried out in oscillating water tunnels and in wave flumes. There are large-scale and small...

The development and hydraulic roughness of subaqueous dunes

Research on bedforms, especially river dunes with focus on the Dutch river Waal, and the effect of these bedforms on the hydraulic roughness of the river. Morphological descriptions, prototype measurements and flume experiments. PhD thesis Utrecht University.

The intrusion of fine suspended sediment into a sandy sediment bed, a literature review

In 2001 a DIOC-project was started at Delft University of Technology on the behaviour of mud in the water column. In this project the behaviour, spreading and settling velocity of fines is studied. After an introductional literature review on the behaviour of fines released due to dredging, the focus was placed on the behaviour of the fines on...

Thin film surface processing by ultrashort laser pulses (USLP)

In this work, we studied the feasibility of surface texturing of thin molybdenum layers on a borosilicate glass substrate with Ultra-Short Laser Pulses (USLP). Large areas of regular diffraction gratings were produced consisting of Laserinduced periodic surface structures (LIPSS). A short pulsed laser source (230 fs-10 ps) was applied using a...

Detailed simulation of morphodynamics: 1. Hydrodynamic model

We present a three-dimensional high-resolution hydrodynamic model for unsteady incompressible flow over an evolving bed topography. This is achieved by using a multilevel Cartesian grid technique that allows the grid to be refined in high-gradient regions and in the vicinity of the river bed. The grid can be locally refined and adapted to the...

Spatial variability of the wave bottom boundary layer over movable rippled beds

Observations of the spatially dependent velocity field over movable bed forms subjected to slightly skewed and asymmetric regular wave forcing were collected. The dynamics between the ripple elements is dominated by coherent vortices, characterized by the swirling strength, and evidenced in the temporal and spectral characterization. Within the...

Detailed simulation of morphodynamics: 3. Ripples and dunes

We present a 3-D physics-based high-resolution modeling approach to the dynamics of underwater ripples and dunes. The flow is modeled by large eddy simulation on a Cartesian grid with local refinements. The sediment transport is modeled by computing pickup, transport over the bed, transport in the water column, and deposition of rigid spherical...

Laser-induced Periodic Surface Structures (LIPSS) on heavily boron-doped diamond for electrode applications

Diamond is known as a promising electrode material in the fields of cell stimulation, energy storage (e.g., supercapacitors), (bio)sensing, catalysis, etc. However, engineering its surface and electrochemical properties often requires costly and complex procedures with addition of foreign material (e.g., carbon nanotube or polymer) scaffolds...

Observations of Time-Dependent Bedform Transformation in Combined Wave-Current Flows

Although combined wave-current flows in the nearshore coastal zone are common, there are few observations of bedform response and inherent geometric scaling in combined flows. Our effort presents observations of bedform dynamics that were strongly influenced by waves, currents, and combined wave-current flow at two sampling locations...

Computational and Experimental Investigation of Biofilm Disruption Dynamics Induced by High-Velocity Gas Jet Impingement

Experimental data showed that high-speed microsprays can effectively disrupt biofilms on their support substratum, producing a variety of dynamic reactions such as elongation, displacement, ripple formation, and fluidization. However, the mechanics underlying the impact of high-speed turbulent flows on biofilm structure is complex under such...

Ripple reduction in piezoelectric micropumps by phased actuation in parallel and damping

Piezoelectric micropumps enable miniaturization in microfluidics for lab-on-a-chip applications such as Organs-on-chips (OoC). However, achieving a steady flow with these micropumps is a significant challenge because of the reciprocating motion of the displacing component. Although dampers are widely preferred for reducing ripples, they are not...

Surface Nanotexturing of Boron-Doped Diamond Films by Ultrashort Laser Pulses

Polycrystalline boron-doped diamond (BDD) films were surface nanotextured by femtosecond pulsed laser irradiation (100 fs duration, 800 nm wavelength, 1.44 J cm⁻² single pulse fluence) to analyse the evolution of induced alterations on the surface morphology and structural properties. The aim was to identify the occurrence of laser...