A PRACTICAL APPLICATION OF AIR LUBRICATION ON A SMALL HIGH SPEED BOAT

This paper discusses how three geometrically similar models are made to investigate the scale law governing the air lubrication on a small high speed boat. Air is supplied behind a step placed on the bottom of the model and relations between flow rates of air and the shapes and areas of the air cavity as well as the resistance reduction are also observed. The reduction of resistance with lubrication of an air cavity and the similarity relations involved are investigated with a series of towing tank tests on geometrically similar models. Three similar models of different size are tested in the towing tank and the results indicate that an introduction of air cavity by artificially supplying air beneath the bottom of a model ship with a backward-facing step is effective for reduction of model resistance. The areas of air cavity and the required flow rates of air, both of which are directly related to the effective wetted surface area and the overall energy saving are found do be dominated by the Froude number scaling. Both the traditional two-dimensional method and Telfer's three-dimensional method seem to be applicable to the extension of the model resistance in the tested range if corrections are made to account for the changes in the frictional resistance caused by the changes in the effective wetted surface area. Based on these finings, a small test boat of practical size is constructed and the effect of air cavity on the reduction of ship resistance is studied. The results confirm the results found in the model tests and assure practical applicability of the air cavity for the resistance reduction of a real ship.

• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/isbn/0080439500
• Corporate Authors:

  Elsevier

  Radarweg 29
  Amsterdam,   Netherlands  1043 NX
• Authors:
  • Jang, J
  • AHN, J
  • Kim, Jinwhan
  • Suh, J-C
  • Kim, H Y
  • LEE, S-H
  • Song, M
• Conference:
  • Practical Design of Ships and Other Floating Structures. Proceedings of the Eighth International Symposium on Practical Design of Ships and Other Floating Strucutres
  • Location: Shanghai, China
  • Date: 2001-9-16 to 2001-9-21
• Publication Date: 2001

Language

• English

Media Info

• Features: Figures; References; Tables;
• Pagination: p. 113-118
• Serial:
  • Volume: 1

Subject/Index Terms

• TRT Terms: Air; Drag forces; Experiments; Friction; Geometric design; High speed craft; Lubrication; Model atmosphere; Resistance tests; Small ships
• Subject Areas: Marine Transportation; Vehicles and Equipment;

Filing Info

• Accession Number: 00819829
• Record Type: Publication
• ISBN: 0080439500
• Files: TRIS
• Created Date: Nov 8 2002 12:00AM