Approximate Calculation of Low Forward Speed Ship Radiation and Diffraction Wave Patterns

Abstract

The present work generalizes a previous procedure for calculating the far field radiation and diffraction waves for a ship a zero speed in the presence of a random sea, to the low forward speed case. The far field waves are calculated by using a Green's function which accounts for linearized terms of the forward speed but neglects higher order terms. This results in a drastic simplification of the arbitrary speed case but retains some of the principal features of forward speed. Extensive calculations are presented for the elevations and slopes of the ship, sea, and superposed waves for various cases of forward speed and sea state. The results are presented in the form of three- dimensional and contour plots. The results show that the effect of forward speed is to increase the magnitudes of the ship waves. Also, forward speed tends to destroy the near symmetry in the ship waves for bow and quartering seas, observed for the zero speed case. Keywords: Low forward speed, Ship radiation, Far field spatial realizations, Random sea waves, Diffraction waves.

Open PDF

Document Details

Document Type
Technical Report
Publication Date
Aug 26, 1988
Accession Number
ADA198998

Entities

People

  • Henry T. Wang

Organizations

  • United States Naval Research Laboratory

Tags

DTIC Thesaurus Topics

  • Computer Programs
  • Computers
  • Coordinate Systems
  • Diffraction
  • Far Field
  • Fluid Dynamics
  • Frequency
  • Grids
  • Military Research
  • Ocean Waves
  • Radiation
  • Ship Hulls
  • Symmetry
  • Synthetic Aperture Radar
  • Three Dimensional
  • Wave Propagation
  • Wind Direction

Readers

  • Electromagnetic Wave Scattering and Antenna Radiation Engineering
  • Marine Hydrodynamics
  • Plasma Physics / Magnetohydrodynamics