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Spectrogram analysis of surface elevation signals due to accelerating ships

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posted on 2023-05-21, 03:51 authored by Pethiyagoda, R, Moroney, TJ, Gregor MacFarlaneGregor MacFarlane, McCue, SW
Spectrograms provide an efficient way to analyze surface elevation signals of ship waves taken from a sensor fixed at a single point in space. Recent work based on a simplified model for the ship's disturbance suggests that matching the spectrogram heat-map patterns to a so-called dispersion curve has the potential for estimating of properties of a steadily moving ship, such as the ship's speed and closest distance to the sensor. Here we extend the theory behind the dispersion curve so that it can be applied to ships accelerating along arbitrary paths and demonstrate how acceleration affects the structure of the associated spectrograms. Examples are provided for a simple model of a ship accelerating/decelerating in a straight line or traveling in a circle with constant angular speed. We highlight a problem with nonuniqueness of the dispersion curve when comparing ships moving along different paths. Finally, we validate the new dispersion curve against experimental results of ship models accelerating in a finite depth basin. Our work will provide a basis for more comprehensive studies that extend the simplified model to take into account the shape of the hull in question.

Funding

Australian Research Council

History

Publication title

Physical Review Fluids

Volume

6

Issue

10

Article number

104803

Number

104803

Pagination

1-23

ISSN

2469-990X

Department/School

Australian Maritime College

Publisher

American Physical Society

Place of publication

United States

Rights statement

©2021 American Physical Society

Repository Status

  • Open

Socio-economic Objectives

Environmentally sustainable transport activities not elsewhere classified; Coastal sea freight transport; Expanding knowledge in the mathematical sciences

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