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#1 |
New Member
Jawahar
Join Date: Nov 2016
Posts: 4
Rep Power: 9 ![]() |
I am solving the pressure poisson equation in BiCG STAB, I am using finite element formulation. the matrix is like this AX=B. Where A is the matrix where each row represents the weight of the surrounding nodes of that node considered(can be taken as the center node which is unknown). X is the unknown node phi and the corresponding B is the known value of the grad times the provisional velocity.
Suppose if there are 9 nodes in 2D, the nodes be numbered from 1 to 9, let 9th node be the center of all other nodes, then the matrix A the row will look like, [weight of node1 weight of node2 .. .. .. .. .. .. .. weight of node 8] the X will be [phi of 9] and B will be [grad times velocity] The problem is when we consider the pressure nodes with known values(i.e., Dirichlet nodes) , then i remove the weight of the nodes from A and add that to B with the given dirichlet values multiplied with the weights of that nodes. This makes the solution to diverge when i give any values other than zero(dirichlet), Can anyone help me how to give this constant dirichlet value in the matrix?? |
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#2 |
Senior Member
Filippo Maria Denaro
Join Date: Jul 2010
Posts: 6,830
Rep Power: 73 ![]() ![]() ![]() |
Are you using a library or is your own-made solver?
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#3 |
New Member
Jawahar
Join Date: Nov 2016
Posts: 4
Rep Power: 9 ![]() |
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#4 |
Senior Member
Filippo Maria Denaro
Join Date: Jul 2010
Posts: 6,830
Rep Power: 73 ![]() ![]() ![]() |
Check if your solver converges with a source term such that the solution is constant, for example 1
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Tags |
dirichlet pressure, finite element method, iterative pressure solver, poisson equation |
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