Reproduction of Velocity Profiles in Estuaries by some One-Dimensional Mathematical Models

For the prediction of dispersion phenomena and of changes in the morphology of an alluvial bottom, a detailed description of the water flow is necessary. The flow in estuaries is a complicated one, partly because of the time-dependence. To isolate this aspect of tidal flow a simplifying one-dimensional (vertical) flow model 1S used. This one...

Turbulent Channel Flow under the action of surface wind-stress

This report deals with experimental research into the wind profile and turbulent current distribution measurements in a wind-water tunnel. Host attention was paid to the water velocity profile as influenced by the wind. It is confirmed that the velocity distribution of the current essentially follows the log law near the air-water interface as...

Local Scour: Influence of an exponential eddy viscosity distribution on the longitudial flow velocity

The general purpose of this research project is to model mathematically the local scour downstream of a structure (2-D). The model has to simulate the development of the scour as a function of the time. Basically two models are necessary namely a flow model and a morphological model. The latter model has to describe the bed and suspended load...

Flow Equations for River Bends Derived by Tensor Calculus and Flow Acceleration in Depth-Averaged Models

Flow equations for application in river bends are derived. Coordinate transformations are achieved by tensor calculus. The momentum equations are formulated in a cylindrical coordinate system and in a cylindrical bed-following coordinate system. The depth-averaged momentum equations in a cylindrical bed-following coordinate system are derived....

Summary of velocity measurements at DHI

A series of comprehensive velocity measurements was carried out on the three dimensional model of the berm breakwater at the Danish Hydraulic Institute (DHI) in September 1995. Those measurements were a part of the research on berm breakwaters within the MAST II programme sponsored by the Commission of the European Communities. The major part of...

Prediction of mean flow data for adabatic 2-D compressible turbulent boundary layers

Estimating Human Movement Parameters Using a Software Radio-based Radar

Radar is an attractive technology for long term monitoring of human movement as it operates remotely, can be placed behind walls and is able to monitor a large area depending on its operating parameters. A radar signal reflected off a moving person carries rich information on his or her activity pattern in the form of a set of Doppler frequency...

Effect of catheter motion on ultrasound M-mode images and corresponding velocity profiles: Development and validation of a simulation model

Background: An ablation catheter with integrated high-frequency single element ultrasound transducers has been developed by Philips Research, which makes it possible to assess tissue-depth and lesion formation in real-time. The interpretation of the acquired ultrasound M-mode images is difficult due to a combination of cardiac motion and motion...

Regions of fresh water influence: The influence of depth on a ROFI

The topic of this paper is the study of the tidal velocity profiles within a region of fresh water influence (referred to as ROFI in this paper). These regions of fresh water influence occur where rivers discharge fresh water into salty seas. The main research question is how depth influences the behaviour of the tidal velocity profile in a...

Surface-wave inversion for a P-velocity profile with a constant depth gradient of the squared slowness

Surface waves are often used to estimate a near-surface shear-velocity profile. The inverse problem is solved for the locally one-dimensional problem of a set of homogeneous horizontal elastic layers. The result is a set of shear velocities, one for each layer. To obtain a P-wave velocity profile, the P-guided waves should be included in the...

Small scale testing of crawler outlet diffusers for plume reduction of offshore mining

Over recent years, there has been an increase in demands for rare and precious minerals worldwide. Mostly this is due to the rise of the world’s population and the drive towards a green energy transition and low carbon economy. Prices are rapidly increasing, and there is an identifiable risk of an increasing supply shortage of raw materials,...

Inversion Methods of the Sound Velocity Profile for Improving the Accuracy of the USBL Positioning System

Remotely Operated Vehicles (ROVs) are positioned relative to an underwater acoustic positioning system: Ultra-Short BaseLine (USBL). The accuracy is affected by refraction artifacts, caused by the variations of the sound velocity in the water column. Accurate positioning would require continuous measuring of the sound velocity profile (SVP)...

Numerical investigation of plastic fragment accumulation against a sluice gate

The ramifications of plastic pollution on the environment are becoming increasingly serious in various forms throughout the world. In this context, rivers are the most important suppliers of plastics entering the marine environment. However, rivers that contain high loads of plastic waste also directly harm the livelihoods of people living near...

Data-driven generation of 4D velocity profiles in the aneurysmal ascending aorta

Background and Objective: Numerical simulations of blood flow are a valuable tool to investigate the pathophysiology of ascending thoratic aortic aneurysms (ATAA). To accurately reproduce in vivo hemodynamics, computational fluid dynamics (CFD) models must employ realistic inflow boundary conditions (BCs). However, the limited availability of...