Description

EX_MAGNETOSTATICS1 Magnetostatic test example.

[ FEA, OUT ] = EX_MAGNETOSTATICS1( VARARGIN ) Magnetostatics test example.

Accepts the following property/value pairs.

Input       Value/{Default}        Description
-----------------------------------------------------------------------------------
sfun        string {sflag2}        Shape function for pressure
iplot       scalar 0/{1}           Plot solution (=1)
                                                                                  .
Output      Value/(Size)           Description
-----------------------------------------------------------------------------------
fea         struct                 Problem definition struct
out         struct                 Output struct

Code listing

 cOptDef = { 'sfun',     'sflag2';
             'iplot',    1;
             'tol',      1.5e-1;
             'fid',      1 };
 [got,opt] = parseopt(cOptDef,varargin{:});
 fid       = opt.fid;


% Geometry and grid generation.
 fea.sdim = { 'x' 'y' };
 fea.grid = rectgrid(10);


% Problem definition.
 fea = addphys( fea, @magnetostatics );
 fea.phys.ms.eqn.coef{1,end} = {  1 };
 fea.phys.ms.eqn.coef{2,end} = {  2 };
 fea.phys.ms.eqn.coef{3,end} = {  3 };
 fea.phys.ms.eqn.coef{4,end} = { -4 };
 fea.phys.ms.sfun            = { opt.sfun };

 fea.phys.ms.bdr.sel = [2 4 3 1];
 fea.phys.ms.bdr.coef{3,end}{1,3} = 6;
 fea.phys.ms.bdr.coef{1,end}{1,4} = 'y';


% Parse and solve problem.
 fea       = parsephys( fea );
 fea       = parseprob( fea );
 fea.sol.u = solvestat( fea, 'fid', opt.fid );   % Call to stationary solver.


% Postprocessing.
 if( opt.iplot>0 )
   figure
   subplot(1,2,1)
   postplot( fea, 'surfexpr', 'Az', 'arrowexpr', fea.phys.ms.eqn.vars{8,2} )
   title( 'Magnetic potential' )
   subplot(1,2,2)
   postplot( fea, 'surfexpr', fea.phys.ms.eqn.vars{5,2}, 'arrowexpr', fea.phys.ms.eqn.vars{9,2} )
   title( 'Magnetic field' )
 end


% Error checking.
 Az  = intsubd( 'Az', fea );
 Mf  = intsubd( fea.phys.ms.eqn.vars{2,2}, fea );
 Scb = intbdr(  fea.phys.ms.bdr.vars{2,2}, fea, 1:4 );
 out.err = [ abs(Az-3.21)/3.21  ;
             abs(Mf-4.9)/4.9    ;
             abs(Scb+2.02)/2.02 ];
 out.pass = all( out.err < opt.tol );


 if ( nargout==0 )
   clear fea out
 end