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Time-frequency analysis of ship wave patterns in shallow water: modelling and experiments

Citation

Pethiyagoda, R and Moroney, TJ and MacFarlane, GJ and Binns, JR and McCue, SW, Time-frequency analysis of ship wave patterns in shallow water: modelling and experiments, Ocean Engineering, 158 pp. 123-131. ISSN 0029-8018 (2018) [Refereed Article]


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DOI: doi:10.1016/j.oceaneng.2018.01.108

Abstract

A spectrogram of a ship wake is a heat map that visualises the time-dependent frequency spectrum of surface height measurements taken at a single point as the ship travels by. Spectrograms are easy to compute and, if properly interpreted, have the potential to provide crucial information about various properties of the ship in question. Here we use geometrical arguments and analysis of an idealised mathematical model to identify features of spectrograms, concentrating on the effects of a finite-depth channel. Our results depend heavily on whether the flow regime is subcritical or supercritical. To support our theoretical predictions, we compare with data taken from experiments we conducted in a model test basin using a variety of realistic ship hulls. Finally, we note that vessels with a high aspect ratio appear to produce spectrogram data that contains periodic patterns. We can reproduce this behaviour in our mathematical model by using a so-called two-point wavemaker. These results highlight the role of wave interference effects in spectrograms of ship wakes.

Item Details

Item Type:Refereed Article
Keywords:ship wakes, spectrograms, shallow water, mathematical model, interference effects
Research Division:Engineering
Research Group:Maritime Engineering
Research Field:Ship and Platform Hydrodynamics
Objective Division:Expanding Knowledge
Objective Group:Expanding Knowledge
Objective Field:Expanding Knowledge in the Mathematical Sciences
Author:MacFarlane, GJ (Associate Professor Gregor MacFarlane)
Author:Binns, JR (Associate Professor Jonathan Binns)
ID Code:126392
Year Published:2018
Funding Support:Australian Research Council (LP150100502)
Web of Science® Times Cited:1
Deposited By:NC Maritime Engineering and Hydrodynamics
Deposited On:2018-06-07
Last Modified:2018-06-14
Downloads:0

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