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problem on boundary definition of a 4th order PDE
Posted Oct 5, 2012, 10:39 p.m. EDT Modeling Tools & Definitions, Parameters, Variables, & Functions Version 4.3 0 Replies
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My PDE is as follows:
uxxxx+2*uxxyy+uyyyy = f
with two types of boundary:
1) u = 0 && uxx+uyy = 0
2) u = 0 && ux*nx+uy*ny = 0 (Neumann Condition)
I split it into two second-order equations:
uxx+uyy = w
wxx+wyy = f
I have got a correct result with the the first type boundary by defining Dirichlet boundary conditions, i.e., u = 0 && w = 0, but I do not have an idea about how to deal with the second type boundary. So far, I have tried following methods, but all failed:
1) add a Neumann Condition (zero flux) or constraint , but it will overriden the Dirichlet boundary conditions. X
2) add a flux/source, but it do not change anything. X
3) add a weak constraint, the solution can not be found. X
Any help will be appreciated!
Thanks!
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Hello Chao Pan
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