AN EXPERIMENTAL STUDY ON SCALE EFFECT ON DIRECTION OF FLOW BEHIND SHIP HULLS MOVING OBLIQUELY

This paper deals with the scale effect of the direction of flow behind a ship's hull in oblique flow. This problem is related to scale effect on rudder forces during manoeuvring motions. The flow directions were determined experimentally, employing three geosim tanker models of 2 m, 4 m and 7 m in length. The measured results were expressed by the coefficient of the flow-straightening effect of a ship body, which was defined as the ratio of a flow direction angle to a drift angle. In addition, on the basis of the assumption to decompose the free stream velocity into lengthwise and crosswise components, calculation for the scale effect on slow-straightening effect was examined. In this calculation method, downwash due to vortex distribution corresponding to hydrodynamic forces on the ship's hull was taken into consideration. Through the study, the authors found that the coefficient becomes larger as ship model length increases. However, the calculated results indicate that the coefficient decreases with increase of the ship model length. Therefore, the problem concerning the prediction method for the scale effect on the characteristics of the flow direction has been left unsolved.

• Supplemental Notes:
  • Kansai Soc Naval Arch J, n 217, March 1992, p 137 [7 p, 11 ref, 2 tab, 11 fig]
• Authors:
  • Yumuro, A
  • Yamamoto, K
• Publication Date: 1992

Language

• Japanese

Subject/Index Terms

• TRT Terms: Flow; Fluid dynamics
• Uncontrolled Terms: Fluid flow; Scale effect
• Old TRIS Terms: Oblique seas
• Subject Areas: Marine Transportation;

Filing Info

• Accession Number: 00703037
• Record Type: Publication
• Source Agency: British Maritime Technology
• Files: TRIS
• Created Date: Aug 14 1995 12:00AM