[Getdp] 2d DC Conduction
Laird Bolt
lbolt1 at irf.com
Tue Feb 28 22:12:58 CET 2006
I apologise in advance for sending such a newbie question to the list. In Payment if someone could
set me on my way I will add my simple example(s) to the main example list.
In an effort to walk (more of a crawl) before I run I am trying to simply
calculate the voltage and current density distribution in a flat bar of copper (no temperature effects assumed)
Fragments for this exist in the mail archives as well as documentation. However,
I must be doing something wrong as my results are always zero when using Dirichlet BC at both ends
and constant (but non-zero) when I use dirichlet at one end and Neumann BC at the other.
I assume that the null Neumann BC along the long sides is implicit.
I have attached my .geo, .pro and solver.par files for the Dirichlet BC (1V at one end 0v at the other)
THe Formulation was :
Formulation {
{ Name Voltage_Steady ; Type FemEquation ;
Quantity {
{ Name Volt ; Type Local ; NameOfSpace Vgrad ; }
}
Equation {
Galerkin { [ invrho[] * Dof {d Volt} , {d Volt} ] ;
In Bar ; Jacobian JVol ; Integration GradGrad ; }
}
}
}
When I run the Dirichlet at both ends I receive a Warning: Null right Hand Side in Linear Equation
which I assume is correct given the problem formulations. I also get an indication that NaN is
being generated in the SOlver (GMRES).
Not surprisingly the Warning goes away when I use the Neumann BC. THe Solver does not report any
NaN problems. <<simpleBar.geo>> <<simpleBar.pre>> <<solver.par>>
Thanks, the mail archives have been a big help
Laird Bolt
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