A generic approach to parameterize the turbulent energy of single-epoch atmospheric delays from InSAR time-series

The observed phase in time series of interferometric synthetic aperture radar (InSAR) products is a superposition of various components. Differential topography, line-of-sight displacements, and differential atmospheric delays are the main contributions and need to be disentangled to derive accurate digital elevation model (DEM), deformation,...

The organization of scalar mixing by coherent structures: An experimental study

Turbulent scalar mixing is prominent in all sorts of situations, being it in air pollution or making tea. However, this does not often lead to a homogeneously mixed fluid, but rather leads to regions of higher concentrations next to regions with significantly lower concentrations. This can be characterized by dividing the concentration field in...

Turbulence Modeling of Wall Jets using the Algebraic Structure Based Model

Report PRE-2628. The Algebraic Structure Based Model (ASBM) of Langer and Reynolds (2003) provides an innovative approach for modeling the turbulent stresses, while incorporating information on the structure of turbulence and providing closure for Reynolds-averaged Navier-Stokes equations. The normal turbulent stresses, for which the ASBM has...

Numerical Investigations of Coherent Structures in Axial Flow in Single Rod-Channel Geometry

In order to ramp up the conversion ratios and burn-up of nuclear reactors, it is inevitable to go to tightly packed fuel rods in the reactor. These nuclear reactors with tightly packed rod-bundles are characterized by interesting flow patterns, different from the ones encountered in regular channel and pipe flows. The correct prediction and...

Transport of suspended particles in turbulent open channel flows

Two experiments are performed in order to investigate suspended sediment transport in a turbulent open channel flow. The first experiment used particle image velocimetry (PIV) to measure the fluid velocity with a high spatial resolution, while particle tracking velocimetry (PTV) was used to measure the velocity of individual sediment particles....

Tomographic particle image velocimetry and its application to turbulent boundary layers

Tomographic Particle Image Velocimetry is a new experimental method developed to study three-dimensional motion in turbulent flows. The technique is an extension of standard PIV and makes use of several simultaneous views of illuminated tracer particles and their three-dimensional reconstruction as a light intensity distribution by means of...

Multiscale Methods in Computational Fluid and Solid Mechanics

The basic idea of multiscale methods, namely the decomposition of a problem into a coarse scale and a fine scale, has in an intuitive manner been used in engineering for many decades, if not for centuries. Also in computational science, large-scale problems have been solved, and local data, for instance displacements, forces or velocities, have...

Multiscale Methods in Computational Fluid and Solid Mechanics

The basic idea of multiscale methods, namely the decomposition of a problem into a coarse scale and a fine scale, has in an intuitive manner been used in engineering for many decades, if not for centuries. Also in computational science, large-scale problems have been solved, and local data, for instance displacements, forces or velocities, have...

Scales and structures in bubbly flows. Experimental analysis of the flow in bubble columns and in bubbling fluidized beds

In this project a detailed experimental analysis was performed of the dynamic flow field in bubbly flows, with the purpose of determining local hydrodynamics and scale effects. Measurements were done in gas-liquid systems (air-water bubble columns) and in gas-solid systems (air-sand bubbing fluidized beds) of different size. Amongst others with...

Turbulence structures affecting stone stability in backward-facing step flow: Experiments by means of Particle Image Velocimetry

Downstream of man-made hydraulic structures, bed protections made of granular material are often used to prevent erosion of the bottom. The stones in the top layer of such granular filters must be able to withstand the hydraulic forces. Probably the best-known formula that is used to determine the stability of granular bed material is the design...

Multiple impinging jet arrays. An experimental study on flow and heat transfer

Because of their high efficiency and their ability to provide high heat transfer rates, impinging jets are applied for rapid cooling and heating in a wide variety of industrial processes. However, the physical phenomena controlling the heat transfer from impinging jets are to a large degree unknown. The goal of the present project was to gain a...

Horizontal Large Eddy Simulation using Delft2D-MOR: The influence of large horizontal eddies on the shape, depth and extent of scour holes

With the morphological models that are in use today, such as Delft2D-MOR, the scour that is calculated near the tip of hard coastal structures like breakwaters and groynes is often underestimated. This is most likely due to the fact that large horizontal turbulent eddies, which are formed when flow goes round these structures, locally enhance...

Turbulent structure in open-channel flows

Ph.D. thesis