Accession Number : AD0782474

Title :   Subharmonic and Divergent Motions of Floating Platforms.

Descriptive Note : Special technical rept. Jan 72-Dec 73,

Corporate Author : SCRIPPS INSTITUTION OF OCEANOGRAPHY LA JOLLA CALIF ADVANCED OCEAN ENGINEERING LAB

Personal Author(s) : Bellows,Donald

Report Date : DEC 1973

Pagination or Media Count : 60

Abstract : Motions of 1/100 and 1/30 scale models of column-stabilized floating platforms in regular waves have been found to fall in two categories: where heave, surge, and pitch motions are in synchronism with the waves, and where major motions are at subharmonic frequencies. Fractional-frequency oscillations have been recorded in a significant number of experiments with a wide array of hydrodynamic forms including single and multiple hull arrays. Corell has investigated half-frequency oscillations using non-linear theory. He shows a restricted window for their inception dependent on wave frequency and amplitude. Through computer simulation using the IBM Continuous System Modeling Program, it has been substantiated that motions in the second category are possible. In fact, there is extremely good agreement between the heave motion from the computer simulation and the heave motion from the model tests in the wave channel. (Modified author abstract)

Descriptors :   *Floating bodies, *Platforms, *Ocean waves, Oscillation, Heaving, Surges, Computerized simulation

Subject Categories : Marine Engineering

Distribution Statement : APPROVED FOR PUBLIC RELEASE