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From: "Baha " <ibaha411@gmail.com>
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Subject: Coupled Boundary Conditions
Date: Mon, 8 Jul 2013 11:19:10 +0000 (UTC)
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Hi all,
I have 4-PDEs and I have coupled Neumann boundary conditions such as: 
@x=d -> D(u1)/Dx = 1/c1*(c2*u4 - c3*u1*(c4 - u4));
@y=0 -> D(u1)/Dy =-1/c1*(c2*u4 - c3*u1*(c4 - u4));
main variables: u1,u2,u3,u4
constants: c1,c2,...

Anybody knows how to implement these boundary conditions? I appreciate...