Difference between revisions of "Removing the Depth Dependence"

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<math>
 
<math>
\phi(x,y,z) = \cosh \big( k (z+d) \big), \quad m \geq 0.
+
\Phi(x,y,z) = \cosh \big( k (z+d) \big) \phi(x,y)
 
</math>
 
</math>
 +
 +
where <math>k</math> is the positive root of the [[Dispersion Equation]]
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then the problem reduces to [[Helmholtz's Equation]]
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 +
<math>\nabla^2 \phi - k^2 = 0 </math>
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 +
in the region not occupied by the scatterers.

Revision as of 11:09, 22 April 2006

If we have a problem in which the water depth is of constant depth [math]\displaystyle{ z=-d/math\gt (we are assuming the free surface is at \lt math\gt z=0 }[/math]) and all the scatters are also constant with respect to the depth then we can remove the depth dependence by assuming that the dependence on depth is given by

[math]\displaystyle{ \Phi(x,y,z) = \cosh \big( k (z+d) \big) \phi(x,y) }[/math]

where [math]\displaystyle{ k }[/math] is the positive root of the Dispersion Equation then the problem reduces to Helmholtz's Equation

[math]\displaystyle{ \nabla^2 \phi - k^2 = 0 }[/math]

in the region not occupied by the scatterers.