The techniques of Laser Induced Fluorescence (LIF) and Dual-Plane Particle Image Velocimetry (PIV) were applied to the investigation of breaking waves and the dispersion of surface films. LIF was used to obtain widescreen images of the concentration distribution of a methanol-rhodamine B film after breaking. Five different wave amplitudes were studied, corresponding to a range of breaker types from weakly spilling to strongly plunging. Spatial and temporal information to quantify the dispersion was extracted from these images, such as the depth reached and area covered by the film, the motion of its centre of mass, dispersion coefficients and exponents, and the fractal dimension of the film-water boundary. The depth measurements and fractal dimension calculations compared well with related work. All three velocity components of the water motion were measured using dual-plane PIV and a single camera. The vector maps obtained revealed the cascade from large to small scale vortices, and the transition from two to three dimensional flow after breaking. A 4-camera system was built, capable of producing sequences of images triggered in rapid succession up to a total of 120 frames per second. Each camera could be individually filtered, allowing the possibility of simultaneous PIV and LIF.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:661624 |
| Date | January 2001 |
| Creators | Schlicke, Ted |
| Publisher | University of Edinburgh |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://hdl.handle.net/1842/14351 |
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