Difference between revisions of "Removing the Depth Dependence"

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</math>
 
</math>
  
where <math>k</math> is the positive root of the [[Dispersion Equation]]
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where <math>k</math> is the positive root of the [[Dispersion Relation for a Free Surface]]
 
then the problem reduces to [[Helmholtz's Equation]]
 
then the problem reduces to [[Helmholtz's Equation]]
  
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in the region not occupied by the scatterers.
 
in the region not occupied by the scatterers.
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 +
[[Category:Linear Water-Wave Theory]]

Revision as of 01:28, 2 June 2006

We are considering the Frequency Domain Problem for linear wave waves. If we have a problem in which the water depth is of constant depth [math]\displaystyle{ z=-d }[/math] (we are assuming the free surface is at [math]\displaystyle{ 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 Relation for a Free Surface 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.