THEORETICAL PREDICTION OF AIR CUSHION WAVE MAKING RESISTANCE: AN INPUT INTO THE SURFACE EFFECT SHIP DESIGN PROCESS

The report is concerned with the theoretical prediction of air cushion wave making resistance. When evaluated numerically on high speed computers it can be used as an input into the surface effect ship design process. The design of surface effect ships is proven to be an exercise in systems integration. Given a general understanding of the main SES systems, a design spiral methodology is proposed. The importance of accurate resistance predictions is demonstrated, and attention shifts to the breakdown of SES drag into its components, with air cushion wavemaking being the principal element in the drag curve peak. Air cushion wavemaking resistance generation is modeled as an asymmetric pressure distribution moving with constant speed along the free surface of a canal of constant width and depth. Previous work in this area is charted, and Newman and Poole's methodology is extended to two new cushion planforms, rectangular main bodies with triangular and elliptic bows. The theory is implemented in a computer program, and the relevant numerical complications are discussed. These two new planforms are numerically evaluated for the constant pressure case and graphically depicted for both infinite and finite depth situations as functions of speed, length to beam ratio, and the width and depth of the canal. This is followed by an analysis of the work presented and recommendations for future work.

  • Corporate Authors:

    Massachusetts Institute of Technology

    Department of Civil Engineering, 77 Massachusetts Avenue
    Cambridge, MA  United States  02139
  • Authors:
    • Fedak, M E
  • Publication Date: 1975-10

Subject/Index Terms

Filing Info

  • Accession Number: 00131218
  • Record Type: Publication
  • Source Agency: Massachusetts Institute of Technology
  • Files: TRIS
  • Created Date: Apr 21 1976 12:00AM