Accession Number : AD0673320

Title :   PROBABILISTIC INSTABILITY AND RESPONSE OF SURFACE SHIPS.

Descriptive Note : Final rept. Feb 66-Sep 67,

Corporate Author : NOTRE DAME UNIV IND DEPT OF ENGINEERING SCIENCE

Personal Author(s) : Strandhagen,Adolf G.

Report Date : JUN 1968

Pagination or Media Count : 40

Abstract : The first part of report is concerned with the probability of instability on a straight course of ships moving in a lateral plane. The hydrodynamic coefficients in the differential equations of motion are considered to be random variates. A criterion for the probability of instability is derived, which is then applied to a MARINER type ship which is known to be near a state of marginal stability on a straight course. The second part of report discusses the probability density functions of the heading rate in a turning maneuver when one or more steering indices are random variates. In particular, the probability density functions are derived for the heading rate response of a ship with a step-type rudder input. The theoretical results are applied to a small cargo ship. It is shown that at very large values of time, the probabilistic response differs considerably from the deterministic response. A procedure for predicting the response in terms of the dimensions and displacement of a ship is also developed and discussed. This procedure appears to be a promising design approach which facilitates the maneuvering capabilities of preliminary designs. (Author)

Descriptors :   (*SHIPS, HYDRODYNAMICS), STABILITY, RESPONSE, EQUATIONS OF MOTION, PROBABILITY DENSITY FUNCTIONS, SYSTEM TEST VESSELS, SHIP HULLS, CARGO SHIPS, STEERING, MARINE RUDDERS

Subject Categories : Aerodynamics
      Marine Engineering
      Fluid Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE