SOME EXPERIMENTAL RESULTS WITH SHIP MODEL ACCELERATION WAVES

The wave resistance of a ship moving at a constant speed can be calculated using information obtained from its wave pattern. One of the basic assumptions in wave survey methods is the existence of a time-independent model speed. In towing tanks initial acceleration is unavoidable. Wehausen (1964) showed that the effect of initial acceleration on wave resistance has a decaying and oscillating character. To study the validity of the theoretical results some experiments were performed. The variation of the measured spectra and the frequencies within the recorded total resistance pitching moment are of interest. Results indicate that models should travel a distance proportional to the square of the Froude number before wave data collection can be begun, that the predicted encounter frequency exists in the recorded total resistance and pitching moment signals, and that special effort is required to avoid initial acceleration waves due to wall effects.

• Corporate Authors:

  United States Naval Academy

  Division of Engineering and Weapons
  Annapolis, MD  United States  21402
• Authors:
  • Calisal, S M
• Publication Date: 1980-2

Media Info

• Pagination: 44 p.

Subject/Index Terms

• TRT Terms: Pitching moment; Ships; Structural models; Wave motion; Wave resistance
• Uncontrolled Terms: Ship models
• Old TRIS Terms: Model testing; Wave pattern analysis
• Subject Areas: Bridges and other structures; Design; Marine Transportation; Vehicles and Equipment;

Filing Info

• Accession Number: 00317460
• Record Type: Publication
• Source Agency: National Technical Information Service
• Report/Paper Numbers: USNA-EW-4-80
• Files: TRIS
• Created Date: Sep 16 1980 12:00AM