THE EFFECTS OF WAVE SPREADING ON THE EXCITING FORCES ON A TENSION LEG PLATFORM

Oil exploration in water deeper than 1000 feet has motivated the development of drilling platforms with dynamic responses superior to those of the conventional jacket structures. One of the most promising of these is the tension leg platform (TLP), a semi-submersible platform held in place by tension members connected to the ocean bottom. This thesis evaluates the wave force transfer function for the TLP in heave, pitch, and roll motions. This is accomplished by assuming the transfer function for a single leg and then extending that result to include the effect of phase differences between forces on multiple legs, including the effect of wave spreading. Cosine squared directional wave spreading is discussed and then dismissed in favor of a Gaussian distribution of wave direction. Using the Gaussian distribution it is shown that when the wave spreading has a standard deviation greater than 0.5 radian the exciting force transfer functions in heave, pitch, and roll converge rapidly to that computed for seas uniformly distributed over all incidence angles. (Author)

  • Supplemental Notes:
    • Availability: Microfiche copies only.
  • Corporate Authors:

    Naval Postgraduate School

    1 University Circle
    Monterey, CA  United States  93943
  • Authors:
    • Dietrich, R A
  • Publication Date: 1979-5

Media Info

  • Pagination: 73 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00326104
  • Record Type: Publication
  • Source Agency: National Technical Information Service
  • Report/Paper Numbers: Master's Thesis
  • Files: TRIS
  • Created Date: Nov 19 1981 12:00AM