Experiments have been performed in wave flumes to investigate the kinematics of flows over a rippled sea bed. Results from Particle Image Velocimetry (PIV) measurements of a variety of flows over sharp crested vortex ripples are presented. Tests were carried out for oscillatory flows, a pure wave, steady currents and a wave plus co-directional currents. PIV generates instantaneous, full-field velocity data and as such is ideal for studying the step-by-step evolution of complex flows. The fine grid of data points in each velocity field is used to derive vorticity data. Both velocity vector maps and vorticity plots are presented. Velocity profiles are obtained and used to calculate physical and apparent roughnesses and friction velocities. The trajectories, circulations and radii of the periodically shed vortices are determined and compared to the predictions of a discrete-vortex model with good agreement within the limitations of the model.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:649856 |
| Date | January 1996 |
| Creators | Earnshaw, Heather Catherine |
| Publisher | University of Edinburgh |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://hdl.handle.net/1842/13760 |
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