FIRST- AND SECOND-ORDER WAVE EFFECTS ON A SUBMERGED SPHEROID

Computations are presented for the linearised force and moment acting on a submerged slender spheroid in regular waves, the resulting pitch and heave motions, and the second-order mean force and moment. These numerical results, which are based on the use of a three-dimensional panel code, are compared with the approximations based on slender-body theory. The accuracy of the slender-body approximation is relatively good for the first-order forces and body motions, but substantial errors are revealed for the second-order mean drift force and pitch moment. Unlike the approximate result, the more correct numerical prediction of the mean pitch moment is non-zero, and generally acts in the bow-down direction in head seas. To explain this result it is shown that the wave elevation directly above the spheroid increases in amplitude from bow to stern, thus causing a greater upward force on the afterbody relative to the forebody.

• Supplemental Notes:
  • J Ship Res, v 35 n 3, Sept 1991, p 183 [8 p, 12 ref, 5 fig]
• Authors:
  • Lee, C H
  • Newman, J N
• Publication Date: 1991

Language

• English

Subject/Index Terms

• TRT Terms: Force; Pitch (Dynamics); Pitch (Dynamics); Waves
• Uncontrolled Terms: Heaving
• Old TRIS Terms: Slender body theory; Submerged bodies; Wave forces on structures
• Subject Areas: Marine Transportation;

Filing Info

• Accession Number: 00701697
• Record Type: Publication
• Source Agency: British Maritime Technology
• Files: TRIS
• Created Date: Aug 14 1995 12:00AM