LATERAL SHIP MOTIONS AND SEA LOADS IN WAVES INCLUDING APPENDAGE AND VISCOUS FORCES

Article type: Research Article

Authors: McTaggart, Kevin

Affiliations: Defence Research Establishment Atlantic, Dartmouth, Nova Scotia, Canada

Abstract: This paper presents a method for including appendage and viscous forces in predictions of lateral plane ship motions and sea loads in waves. Because sea loads arise from relatively small differences between large quantities, forces acting on the ship must be treated in a consistent manner for motion and sea load computations. The present implementation with strip theory correctly gives zero sea loads at the aft end of the ship. Comparisons with experiments for a narrow stern warship model show good agreement and demonstrate the importance of appendage forces. Additional comparisons for a transom stern frigate show inferior agreement for roll and torsion, suggesting that the current treatment of appendage and viscous forces should be included in a three-dimensional ship motion and sea load program.

Journal: International Shipbuilding Progress, vol. 47, no. 450, pp. 141-160, 2000