A Modified Expression for Evaluating the Steady Wave Pattern of a Ship
Abstract
The study presents a modified mathematical expression for the wave- spectrum function in the Fourier representation of the wave pattern of a ship advancing at constant speed in calm water. This new expression is obtained from the well-known usual expression via several applications of Stokes' theorem for combining the integrals along the top waterline and over the hull surface of the ship. The modified expression for the wave-spectrum function is considerably better suited than the usual expression for accurate numerical evaluation, notably for evaluating the short divergent waves of interest for remote sensing of ship wakes, because the significant numerical cancellations occurring between the waterline and hull integrals in the usual expression are automatically and exactly accounted for in the modified mathematical expression, as is demonstrated mathematically and confirmed numerically. Whereas the values of both the velocity potential and its gradient at the hull are required in the usual expression for the wave-spectrum function, the new expression only involves the tangential velocity at the hull, not the potential. This new expression thus defines the wave-spectrum function in terms of the speed and the size of the ship, the hull form, and the tangential velocity at the mean hull surface.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 1988
- Accession Number
- ADA205541
Entities
People
- Francis Noblesse
- Woei-min Lin