[Getdp] Help on problem formulation - constraits
Ivan Vicente Janvrot Miranda
janvrot at infolink.com.br
Mon Apr 29 03:45:08 CEST 2002
Dear All
I' using this excellent program in a 3D study a 1/4" thick steel plate
with a magnet at each side and a hole in the middle. The problem
addresses the case of a very wide plate with wide magnets and a small
hole, which is the region of interest.
I defined the geometry with gmsh and generated the mesh for one quadrant
of the problem to exploit symetry. There is an air volume above and
below the plate. Attached is a .jpg with a schematic.
I'm using the suggestion found in the FAQ (for gmsh t5.geo) given
below, but I'm not able to define the constraints to apply to Surfaces
A to D and Upper and Lower air bound surfaces.
I' would be gratefull for any help.
Thanks in advance.
Janvrot IVM
janvrot at infolink.com.br
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/*
Magnetostatic problem (scalar magnetic potential), based on t5.pro from
FAQ
*/
Group {
Steel = Region[ 1 ];
Magnet = Region[ 2 ];
Air = Region[ 3 ];
Domain = Region[ {Magnet, Steel, Air} ];
// SurfaceA = ...; // uniform until infinity
// SurfaceB = ...; // out interest
// SurfaceC = ...; // simetry plane
// SurfaceD = ...; // simetry plane
// UpperAirBoundSurface = ...;
// LowerAirBoundSurface = ...;
}
Function {
mu0 = 4.e-7 * Pi ;
murSteel = 1000;
murMagnet = 1;
mu[Steel] = murSteel * mu0;
mu[Magnet] = murMagnet * mu0;
mu[Air] = mu0;
hc[Magnet] = Vector[920000., 0., 0.];
}
Jacobian {
{ Name MyJac;
Case {
{ Region All; Jacobian Vol; }
}
}
}
Integration {
{ Name MyInt;
Case {
{ Type Gauss;
Case {
{ GeoElement Tetrahedron; NumberOfPoints 5; }
}
}
}
}
}
FunctionSpace {
{ Name Hgrad_phi; Type Form0;
BasisFunction {
{ Name sn; NameOfCoef phin; Function BF_Node;
Support Domain; Entity NodesOf[ All ]; }
// uncomment the following for 2nd order interpolation:
//{ Name sn2; NameOfCoef phin2; Function BF_Node_2E;
// Support Domain; Entity EdgesOf[ All ]; }
}
}
}
Formulation {
{ Name MagSta_phi; Type FemEquation;
Quantity {
{ Name phi; Type Local; NameOfSpace Hgrad_phi; }
}
Equation {
Galerkin { [ - mu[] * Dof{d phi} , {d phi} ];
In Domain; Jacobian MyJac; Integration MyInt; }
Galerkin { [ - mu[] * hc[] , {d phi} ];
In Magnet; Jacobian MyJac; Integration MyInt; }
}
}
}
Resolution {
{ Name MagSta_phi;
System {
{ Name A; NameOfFormulation MagSta_phi; }
}
Operation {
Generate[A]; Solve[A]; SaveSolution[A];
}
}
}
PostProcessing {
{ Name MagSta_phi; NameOfFormulation MagSta_phi;
Quantity {
{ Name phi; Value { Local { [ {phi} ]; In Domain; Jacobian MyJac;}
} }
{ Name b; Value
{
Local { [ - mu[] * {d phi} ]; In Domain; Jacobian MyJac;
}
Local { [ - mu[] * hc[] ] ; In Magnet; Jacobian MyJac;
}
}
}
}
}
}
PostOperation {
{ Name phi; NameOfPostProcessing MagSta_phi;
Operation {
Print[ phi, OnElementsOf Domain, File "phi.pos"];
Print[ b, OnElementsOf Domain, File "b.pos"];
Print[ b, OnCut {{0,0,0.004}{1,0,0.004}{1,1,0.004}}, File "bc.pos"
];
// Print[ b, OnCut {{0,0,-0.002}{1,0,-0.002}{1,1,-0.002}}, File
"bc.pos" ];
}
}
}
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