SHIP 
SURFACE CURRENTS DUE TO VORTICES 
m (TYPICALLY 1 - 100 cm/s) 
NET REARNARD VELOCITY 
(TYPICALLY 1 - 10 cm/s) 
  
DARK AREA——7] 
  
  
OCCASIONAL BRIGHT LINES —»- 
€ eR en. 
Ae 
HULL VORTICES 
(NOT TO SCALE) 
Figure 9. Diagram of Turbulent Wake Structure Showing Possible Role of 
Vortices and Net Rearward Velocity Within Turbulent Region 
(after Swanson, 1984) 
~WIND (~ m/s) 
  
  
Q. 4 
I 
I 
! 
in 
| 
— ij! 
m -271 |. i \ 
ea | \ 
x \ 
= — 4 
Suny — 
um — 
z I 
ul I 
— —-S41 +7 \ | 
= \ 
uJ \ 
2 | 
= 
= LA PES MODEL 
À I 
Cs spans J ACTUAL 
= FI 
M 
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li 
-10.82 + + + + +- + + + + + + + + + + 4 
a. 33.52 107.64 161.46 215.28 269.1 322.92 376.74 430.56 
A 
A DISTANCE (METERS) 
Figure 10. Graphical Comparison of Predicted Radar Backscatter Variation 
Based on Vortex Model (dashed) and Actual Backscatter 
Measurements (solid) 
421