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Wave equation 1D

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Hello,

I'm actually using Comsol 4.3 to solve the wave equation 1D (PDE (waeq)) with the form :
e*d2u/dt2 + grad(-C*grad(u)) = f.
I put : e is the mass density and C is the elastic constant, to define the acoustic speed in this wire. Then I send a cosine wave from left to right. The right end is free.

But it is very strange that there is a supplement signal which goes with a double speed. In addition, the wavelength of this signal is in the order of the mesh.

Could you give me some advices ?

Thank you very much in advance.

Anne

0 Replies Last Post 16 sept. 2013, 05:22 UTC−4
COMSOL Moderator

Hello Anne Nghiem

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