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Old   July 16, 2013, 11:24
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amir mokhtare
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i have a mathematical quastion
i wana drive the weak formulation of this pde
-div( 1/sqrt(1+grad|u|^2) * grad(u) ) = 0
with u=x^2 on the boundary
could anybody help me,please?
thank you
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Old   July 16, 2013, 14:08
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Reza
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I'm probably missing something in your question. Are you after something like using the divergence theorem to get:

integral of (<F,grad(phi)> dV) over V - integral of (phi <F,n> dS) over boundaries of V = 0, where F=grad(u)/sqrt(1+grad|u|^2) and <.,.> is an inner (dot) product, and then using the boundary conditions to get a value for the second integral?
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Old   July 17, 2013, 00:20
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amir mokhtare
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yes but i need more simple form that include test functions to
enter in Comsol
thank you for your reply
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Old   July 17, 2013, 11:26
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Reza
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Don't have any experience with COMSOL, so don't know what is the format that it is asking for, but in the equation that I wrote, phi was the test function.
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