A DISCRETE VORTEX METHOD FOR PREDICTING HYDRODYNAMIC LOADS ON SIDEWALLS OF SURFACE EFFECT SHIPS

A discrete vortex method has been formulated for calculating the hydrodynamic loads on SES sidewalls in an inviscid separated flow due to vorticity. A rigid, flat, free surface is assumed. The vortex system consists of a bound vortex lattice attached on the lifting surface, a single free tip vortex core from the side edge, and free vortex lines emanating from the trailing edge. The presence of these free vortices accounts for the nonlinear effects. Single and double sidewalls of different area aspect ratios have been considered for various geometrical arrangements and flow conditions. It was found that with the present single tip vortex model, the accuracy of the results improved with increasing aspect ratio. Side forces predicted for small AR cases were higher than given by other methods. The effect of wall interference was significant for double sidewalls with increases in length-to-beam ratio, or area aspect ratio, or yaw angle. (Author)

• Corporate Authors:

  David Taylor Naval Ship R&D Center

  Aviation and Surface Effects Department
  Bethesda, MD  United States  20084
• Authors:
  • Tai, T C
  • Whitehead, R E
• Publication Date: 1977-9

Media Info

• Pagination: 63 p.

Subject/Index Terms

• TRT Terms: Boundary layer separation; Equations; Flow; Hydrodynamic pressure; Hydrodynamics; Inviscid fluids; Mathematical prediction; Moments (Mechanics); Ratios; Surface effect ships; Vortices; Wall effect; Walls
• Uncontrolled Terms: Aspect ratio
• Old TRIS Terms: Hydrodynamic forces; Inviscid flow; Moments; Separated flow; Vortex theory
• Subject Areas: Data and Information Technology; Design; Hydraulics and Hydrology; Marine Transportation;

Filing Info

• Accession Number: 00174468
• Record Type: Publication
• Source Agency: National Technical Information Service
• Report/Paper Numbers: DTNSRDC-77-0035 Intrm Rpt., Aero-1240
• Files: TRIS
• Created Date: Mar 14 1978 12:00AM