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):

Report Date:

1968-06-01

Pagination or Media Count:

40.0

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

Subject Categories:

  • Aerodynamics
  • Marine Engineering
  • Fluid Mechanics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE