FEM4EllipticPDE/examples/borehole/boreholeMagnetPlus.geo

/**
 *  Trevor P. Irons, XRI Geophysics, LLC
 *  Test of Coloumbic Magnetic Potential
 */


Function Cyl
    // centre
    pp0 = newp; Point(pp0) = {   0,    0, D0, lc2};

    // Points defining outer ring
    pp1 = newp; Point(pp1) = { R2,   0, D0, lc2};
    pp2 = newp; Point(pp2) = {  0,  R2, D0, lc2};
    pp3 = newp; Point(pp3) = {-R2,   0, D0, lc2};
    pp4 = newp; Point(pp4) = {  0, -R2, D0, lc2};

    cc1 = newc; Circle(cc1) = {pp1, pp0, pp2};
    cc2 = newc; Circle(cc2) = {pp2, pp0, pp3};
    cc3 = newc; Circle(cc3) = {pp3, pp0, pp4};
    cc4 = newc; Circle(cc4) = {pp4, pp0, pp1};

    ll1 = newl; Line Loop(ll1) = {cc1, cc2, cc3, cc4};

    ss1 = news; Plane Surface(ss1) = {ll1};
    //v1 = newv; v1 =
    //newv vol2;
    vol2[] = Extrude {0, 0, D1-D0} { Surface{ss1}; };

Return

lc = 5e-2;   // Target element size
R = .05;   // Magnet Radius
D0 = 10;   // Top of magnet
D1 = 11;   // Bottom of magnet


p0 = newp; Point(p0) = { 0, 0, D0, lc};
p1 = newp; Point(p1) = { R, 0, D0, lc};
p2 = newp; Point(p2) = { 0, R, D0, lc};
p3 = newp; Point(p3) = {-R, 0, D0, lc};
p4 = newp; Point(p4) = { 0,-R, D0, lc};

c1 = newc; Circle(c1) = {p1, p0, p2};
c2 = newc; Circle(c2) = {p2, p0, p3};
c3 = newc; Circle(c3) = {p3, p0, p4};
c4 = newc; Circle(c4) = {p4, p0, p1};


ll0 = newl; Line Loop(ll0) = {1,2,3,4};
Plane Surface(6) = {5};
vol2[] = Extrude {0,0,D1-D0} {
  Surface{6};
};


/*
vol1[] = Extrude {0, 0, D1-D0} { Line{c1:c4}; };
*/
////////////////////////////////////////////////////
// Big Cylinder
////////////////////////////////////////////////////
/*
lc2 = 1e-2;    // Target element size
R2 =  .175;    // Minimum Radius
D0 = 9.75;     // Top of mesh
D1 = 11.25;    // Bottom of mesh

Call Cyl;

//newv vol3;
//Compound Volume(vol3) = {vol1[1], vol2[1]};


Field[1] = Attractor;
Field[1].NodesList = {p0,p1,p2,p3,p4};

Field[2] = Threshold;
Field[2].IField = 1;
Field[2].LcMin = lc / 5;
Field[2].LcMax = lc;
Field[2].DistMin = 0.05;
Field[2].DistMax = 0.5;

// Use minimum of all the fields as the background field
Field[3] = Min;
Field[3].FieldsList = {2};
Background Field = 2;

// Don't extend the elements sizes from the boundary inside the domain
Mesh.CharacteristicLengthExtendFromBoundary = 0;
Mesh.CharacteristicLengthFromPoints = 1 ;
*/
Mesh 3;

/*
Delete { Volume{vol1[1]}; }
Delete { Volume{vol2[1]}; }

Delete { Point{p0}; }
Delete { Point{p1}; }
Delete { Point{p2}; }
Delete { Point{p3}; }
Delete { Point{p4}; }

Delete { Line{c1}; }
Delete { Line{c2}; }
Delete { Line{c3}; }
Delete { Line{c4}; }
*/
//Delete { Line{ll0}; }
//Delete { Volume{vol2}; }






/*
////////////////////////////////////
// South Pole

Point(8)  = { 0,  -0.0001, D0, lc};
Point(9)  = { R,  -0.0001, D0, lc};
Point(10) = { 0, -R, D0, lc};
Point(11) = {-R,  -0.0001, D0, lc};

// Connect up the points
Circle(12) = {11, 8, 9};
Line(13) = {9, 11};
Line Loop(14) = {12, 13};
Plane Surface(15) = {14};
*/

//////////////////////////////////////
// Extrude magnet
//Extrude {0, 0, D1-D0} { Surface{7};  }
//Extrude {0, 0, D1-D0} { Surface{15}; }

/*
// Large Bounding box
Point(116)  = {X0, Y0, Z0};
Point(117)  = {X1, Y0, Z0};
Point(118)  = {X1, Y1, Z0};
Point(119)  = {X0, Y1, Z0};
Line(120) = {116,117};
Line(121) = {117,118};
Line(122) = {118,119};
Line(123) = {119,116};
Line Loop(124) = {120, 121, 122, 123};
Plane Surface(125) = {124};
Extrude {0, 0, Z1-Z0} { Surface{125}; }
*/

//////////////////////////////////////
// Volumes

//Physical Volume("plus") = {2};
//Physical Volume("minus") = {1};
//Physical Volume("background") = {3};
/*
Delete {
  Surface{9};
}
Delete {
  Surface{13};
}
Delete {
  Surface{17};
}
Delete {
  Surface{21};
}
*/
Compound Volume(49) = {1};
Compound Volume(50) = {49, 1};