Experimental investigations of the velocity characteristics related to turbulent propeller-jet flow were carried out. Laser Doppler Anemometry (LDA) was used as the measurement technique. The investigations were performed in a free-surface tank, large enough to allow the unhindered expansion of unconfined propeller jets at bollard-pull. Comprehensive time-averaged (mean) and instantaneous real-time (blade-to- blade) velocity measurements were taken to assess the magnitude and location of the velocities that produce serious seabed scour. The results identify that the propeller blades play an important role in the development of the instantaneous velocity fields up to a downstream distance of two propeller diameters. Beyond this distance, the time-averaged form of measurement resolved all necessary information regarding the axial, radial and rotational velocity components. Establishing methods through which the characteristics of all three-velocity components can be determined using linear regression techniques has been carried out to extend the applications of existing semi-empirical equations. In the absence of suitable linear approximations of the main velocity characteristics, Artificial Neural Network (ANN) programmes were developed as an alternative method of determining the three-dimensional flow fields of a diffusing propeller jet produced in the confines of a harbour basin.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:486226 |
| Date | January 2007 |
| Creators | Kee, Charmaine |
| Publisher | Queen's University Belfast |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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