MEASUREMENT OF HYDRODYNAMIC SWAY FORCE ACTING ON TWO- DIMENSIONAL MODELS OF SMALL SHIP

A large amplitude forced sway motion test was conducted to investigate the effect of hull forms to the non-linear sway force and moment. Three two-dimensional round-chine models with dead-rise angle of 10, 20, and 30 degrees were used. In total the test was carried out on nine hull forms, using the three-round-chine models with/without hard-chine pieces and skegs. It is shown that a conventional linear integral equation method can almost evaluate the acceleration component of sway force and moment, but cannot evaluate the damping component, because the drag component occupies the main or non-negligible part of sway damping. It is also shown that the rolling moment by the sway motion becomes very asymmetric when flow separation occurs locally at the vicinity of the bottom centre or of the chine. The asymmetry becomes small when the separated flow covers the whole bottom, which happens on the models with skeg or with large dead-rise angle. The paper also deals with the force and moment of drift motion at a constant speed. The characteristics of the heeling moment is similar to that of sway motion. The moment works to increase the heel angle when the ship moves to the direction of heeling but it becomes small if the model makes a large separation region.

• Supplemental Notes:
  • J Soc Naval Arch Japan, v 178, Dec 1995, p 147 [13 p, 14 ref, 16 fig]
• Authors:
  • ISHIDA, S
  • Fujiwara, T
• Publication Date: 1995

Language

• Japanese

Subject/Index Terms

• TRT Terms: Hulls; Ship motion; Swaying
• Old TRIS Terms: Hull form
• Subject Areas: Marine Transportation; Vehicles and Equipment;

Filing Info

• Accession Number: 00728013
• Record Type: Publication
• Source Agency: British Maritime Technology
• Files: TRIS
• Created Date: Nov 4 1996 12:00AM