Session: 12-02-02 Wave-Structure Interactions II

Paper Number: 126667

126667 - Time-Harmonic Ship Waves From the Perspective of an Earth-Fixed Observer 

Similar to steady flows, time-harmonic flows around a ship advancing in waves are usually described in the coordinate system moving with the ship's average speed. Within this moving reference system, detailed descriptions of ship waves have been made in many previous studies. Recent works by Noblesse (2000) and Chen (2004) revealed that essential physical features such as different wave systems and their wavelengths, cusp angles, phase, and group velocities, are directly related to wavenumber curves determined by the dispersion relation on the mathematical Fourier plane. Insightful physical results have been achieved and applied in developing numerical tools to predict ship seakeeping.

However, the description of time-harmonic ship waves in the earth-fixed coordinate system is missing although a few studies exist on steady ship waves like that by Liang et al (2023). It is not trivial to transform results in the moving coordinate system to the fixed coordinate system. Much caution is needed to obtain consistently the phase and group velocities which are closely associated with wave crestlines. In the present study, after having summarized classical results in the moving coordinate system, detailed analyses of time-harmonic ship waves in the earth-fixed coordinate system are presented with numerical illustrations. The results obtained in both coordinate systems are believed to be useful in the prediction of ambient waves due to the passage of ships.

Noblesse F. (2000) Analytical representation of ship waves (23^rd Weinblum Memorial Lecture), NSWCCD-TR-2000/011, pp1-35.

Chen X.B. (2004) Analytical features of unsteady ship waves. In Advances in Engineering Mechanics -- Reflections and Outlook edited by Chwang, A. T. and Teng, M. H. and Valentine, D. T., World Scientific Publishing, pp371-89.

Liang H., Li Y. and Chen X.B. (2023) Physical properties of the ship wake and its detection. 38^th IWWWFB, Michigan (USA).

 

Presenting Author: Xiaobo Chen Bureau Veritas

Presenting Author Biography: Dr. Xiaobo Chen is a research scientist, a graduate of the Tsinghua University (China) awarded in 1983 as a distinguished graduating student. In 1988, he got his Ph.D. in Hydrodynamics of Ecole Centrale Nantes (France). After the post-doctoral fellowship at Institute Français du Pétrole, he joined Bureau Veritas in 1991. He has worked in the Research Department of the Marine Division, and then the Head of Hydrodynamics & Mooring Section. He has been a member of the IACS working group WD-SL and the ISSC Technical Committee on Loads, and the chairman of recent IACS-HPT01 working on the harmonization of Common Structure Rules.

Authors:

Xiaobo Chen Bureau Veritas
Hui Liang Technology Centre for Offshore and Marine, Singapore