Near-Field Ship Wake Signature Modeling and Simulation
Final rept. Mar 1992-Dec 1993
ENVIRONMENTAL RESEARCH INST OF MICHIGAN ANN ARBOR ADVANCED CONCEPTS DIV
Pagination or Media Count:
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.
- Marine Engineering