ON THE SCALE EFFECT ON THRUST DEDUCTION

On the basis of a large number of theoretical and experimental investigations, the mechanism behind the thrust deduction problem is described. Equations connecting the displacement thrust deduction with the displacement and frictional wake fractions and the propeller load coefficient are put forward and comparisons are made between results obtained by these equations and those recorded during self propulsion tests. Different explanations of the deviations observed are discussed. It is shown that the scale effect on thrust deduction largely depends upon how the displacement wake is assumed to vary with model size. Calculations carried out indicate, however, that this scale effect is in most cases small compared with the measurement errors inherent in the model tests. The scale effect seems to be significant only for full form ships where, under unfavorable conditions, the propeller can change the flow along the stern considerably. Special tests to detect and avoid these extreme flow conditions are recommended.

• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/issn/03060209
• Corporate Authors:

  Royal Institution of Naval Architects

  10 Upper Belgrave Street
  ,   United States 
• Authors:
  • Dyne, G
• Publication Date: 1973-7

Media Info

• Features: References;
• Pagination: p. 187-200
• Serial:
  • Naval Architect
  • Issue Number: 3
  • ISSN: 0306-0209

Subject/Index Terms

• TRT Terms: Thrust; Wakes
• Uncontrolled Terms: Scale effect
• Old TRIS Terms: Thrust deduction; Wake fraction
• Subject Areas: Design; Marine Transportation;

Filing Info

• Accession Number: 00050991
• Record Type: Publication
• Source Agency: Engineering Index
• Files: TRIS
• Created Date: Feb 20 1974 12:00AM