FEM4EllipticPDE/examples/grav/sphereBox.geo

/* This file is part of Lemma, a geophysical modelling and inversion API.
 * More information is available at http://lemmasoftware.org
 */

/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/.
 */

D0 = 10;          // Top of magnet
D1 = 11;          // Bottom of magnet
radius = 2.25;     // Radius of the damn thing

lc = radius;   //  0.25;   // Target element size

// Total Solution Space
Box = 3*radius; // The down side of potential
X0 = -Box;
X1 =  Box;
Y0 = -Box;
Y1 =  Box;
Z0 = -Box;
Z1 =  Box;

cellSize=lc; //300;
dd = 0 ; //  1e-5; //cellSize; // .01;
pio2=Pi/2;


/////////////////////////////////////
// Large Bounding box
pp = newp;
Point(pp)    = {X0, Y0, Z0, lc};
Point(pp+1)  = {X1, Y0, Z0, lc};
Point(pp+2)  = {X1, Y1, Z0, lc};
Point(pp+3)  = {X0, Y1, Z0, lc};


lv = newl;
Line(lv) = {pp,pp+1};
Line(lv+1) = {pp+1,pp+2};
Line(lv+2) = {pp+2,pp+3};
Line(lv+3) = {pp+3,pp};
Line Loop(lv+4) = {lv, lv+1, lv+2, lv+3};

// Hard coded doom
Plane Surface(125) = {lv+4};

//v = newv;
v[] = Extrude {0, 0, Z1-Z0} { Surface{125}; };

// // Calculate offset effect
// theta = Asin(dd/radius);
// rr = radius * Cos(theta);
//
// ///////////////////////////////////
// // Positive half sphere
// // create inner 1/8 shell
// p0 = newp;
// Point(p0)   = {      0,   0,       0, cellSize}; // origin
// Point(p0+1) = {    -rr,   0,      dd, cellSize};
// Point(p0+2) = {      0,  rr,      dd, cellSize};
// Point(p0+3) = {      0,   0,  radius, cellSize};
// Point(p0+4) = {      0,   0,      dd, cellSize}; // origin
//
// c0 = newc;
// Circle(c0  ) = {p0+1, p0+4, p0+2};       // Tricky, This one needs to be offset!
// Circle(c0+1) = {p0+3, p0, p0+1};
// Circle(c0+2) = {p0+3, p0, p0+2};
//
// Line Loop(10) = {c0, -(c0+2), c0+1} ;
// Ruled Surface (60) = {10};
//
// ////////////////////////////////////////////////////////////
// // Negative half sphere
// p = newp;
// Point(  p) = {      0,      0,            0, cellSize};
// Point(p+1) = {    -rr,      0,          -dd, cellSize};
// Point(p+2) = {      0,     rr,          -dd, cellSize};
// Point(p+3) = {      0,      0,      -radius, cellSize};
// Point(p+4) = {      0,      0,          -dd, cellSize};
//
// cc = newc;
// Circle(cc  ) = {p+1, p+4, p+2};
// Circle(cc+1) = {p+3, p,   p+1};
// Circle(cc+2) = {p+3, p,   p+2};
//
// Circle(cc+3) = {p+3, p, p+2};
// Circle(cc+4) = {p+3, p, p+2};
// Circle(cc+5) = {p+3, p, p+2};
//
// ccl = newl;
// Line(ccl) = { p0+3, p+3 };
//
// Line Loop(11) = {cc, -(cc+2), cc+1} ;
// Ruled Surface (61) = {11};
//
// // create remaining 7/8 inner shells
// t1[] = Rotate {{0,0,1},{0,0,0},pio2  } {Duplicata{Surface{60};}};
// t2[] = Rotate {{0,0,1},{0,0,0},pio2*2} {Duplicata{Surface{60};}};
// t3[] = Rotate {{0,0,1},{0,0,0},pio2*3} {Duplicata{Surface{60};}};
// //
// t4[] = Rotate {{0,0,1},{0,0,0},pio2  } {Duplicata{Surface{61};}};
// t5[] = Rotate {{0,0,1},{0,0,0},pio2*2} {Duplicata{Surface{61};}};
// t6[] = Rotate {{0,0,1},{0,0,0},pio2*3} {Duplicata{Surface{61};}};
//
// /* This is GOOD */
// Surface{60} In Volume{v[1]};
// Surface{t1[0]} In Volume{v[1]};
// Surface{t2[0]} In Volume{v[1]};
// Surface{t3[0]} In Volume{v[1]};
//
// Surface{61} In Volume{v[1]};
// Surface{t4[0]} In Volume{v[1]};
// Surface{t5[0]} In Volume{v[1]};
// Surface{t6[0]} In Volume{v[1]};
//
// ///////////////////////////////////////////////
// // Attractor Field
//
// //Field[1] = Attractor;
// //Field[1].NodesList = {p}; //0, p0+1, p0+2, p0+3, p0+4, p, p+1, p+2, p+3, p+4};
//
// //Field[2] = MathEval;
// //Field[2].F = Sprintf("(2.25 - F1)^2 + %g", cellSize*10 );  // WORKS
// //Field[2].F = Sprintf("(%g - F1)^2 + %g", radius, 2*cellSize );
// //Background Field = 2;
//
// // Don't extend the elements sizes from the boundary inside the domain
// //Mesh.CharacteristicLengthExtendFromBoundary = 0;
//
// Physical Volume(1) = {v[1]};

// To create the mesh run
// gmsh sphere.gmsh -2 -v 0 -format msh -o sphere.msh
//gmsh -3 -format msh1 -o outfile.msh sphere.geo