Near-Field Ship Wake Signature Modeling and Simulation

Abstract

A frequently observed characteristic of Synthetic Aperture Radar (SAR) imagery of moving ships is an area of increased backscatter immediately behind the ship extending approximately one ship length. The region causing these signatures has been termed the near-field disturbed water (NFDW) region of the ship. In this report a simple prediction model for these signatures is presented. This model utilizes a Fourier transform solution for the Kelvin wake along with a numerical procedure for calculating the hull pressure distribution. The model appears to predict the breaking regions more or less correctly for ship hulls having a rectangular stern, but over predicts the extent of the breaking regions for non-rectangular stern shapes. This limitation is apparently due to the fact that energy dissipation due to wave breaking has not been included. Outputs from the NFDW model are used to simulate a SAR image of the NFDW region and encouraging agreement between the appearance of the simulated and actual SAR images is found. The dependence of the NFDW with ship speed is in agreement with observations.

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Document Details

Document Type
Technical Report
Publication Date
Jan 01, 1994
Accession Number
ADA277175

Entities

People

  • David R. Lyzenga
  • N. Malinas

Organizations

  • Environmental Research Institute of Michigan

Tags

Communities of Interest

  • Ground and Sea Platforms

DTIC Thesaurus Topics

  • Aerial Photographs
  • Coordinate Systems
  • Doppler Effect
  • Dynamic Pressure
  • Electromagnetic Radiation
  • Equations
  • Hydrostatic Pressure
  • Measurement
  • Near Field
  • Photographs
  • Pressure Distribution
  • Radar Cross Sections
  • Radial Velocity
  • Ship Hulls
  • Simulations
  • Synthetic Aperture Radar
  • Waves

Fields of Study

  • Physics

Readers

  • Atmospheric Science / Meteorology, specifically Wind Wave Turbulence.
  • Computational Modeling and Simulation
  • Maritime Security/Maritime Homeland Security