FEATool Multiphysics  v1.14
Finite Element Analysis Toolbox
gridgen_scale.m File Reference


GRIDGEN_SCALE Grid generation with scaling.

[ GRID, STATS ] = GRIDGEN_SCALE( SIN, VARARGIN ) Generates a scaled grid/mesh for the geometry defined by the objects in SIN by calling an external grid generation algorithm. SIN can be either a valid fea problem struct with geometry defined in SIN.geom.objects, a cell array of multiple geometry objects, or a single geometry object. The geometry is first scaled according to the input arguments, the scaled geometry is then meshed, and finally the mesh the re-scaled to fit the original geometry. Accepts the following property/value pairs are available with the default grid generation algorithm.

Property    Value/{Default}           Description
axis        int {1}                   Scaling axis (1=x, 2=y, 3=z)
p_scal      scalar/array {midpoint}   Scaling points (along axis)
s_scal      scalar/array {[]}         Scaling factors (per scaling point)
varargin    pv pairs {defaults}       Property/value pairs to pass to gridgen

P_SCAL are coordinates along the AXIS to identify geometry objects to scale. Geometry objects for which P_SCAL falls within the bounding boxes will be scaled with the corresponding S_SCAL entry.

  1) 3x1 rectangle scaled by 1/3 in the x-direction.

  grid = gridgen_scale( gobj_rectangle(0,3), 's_scal', 1/3 );
  plotgrid( grid )

  2) Polygon scaled by 1/5 in the y-direction.

  grid = gridgen_scale( gobj_polygon([0 0;1 0;0.8 2;1.1 5; 0 5]), 'axis', 2, 's_scal', 1/5 );
  plotgrid( grid )

  3) Cylinder scaled by 1/6 in the z-direction.

  grid = gridgen_scale( gobj_cylinder([0,0,0],0.5,5,3), 'axis', 3, 's_scal', 1/6 );
  plotgrid( grid )

  4) Scaling three parallel cylinders in a block (only scaling section with cylinders).

  b1 = gobj_block(-0.75,3.25,-0.75,0.75,-0.5,5.5);
  c1 = gobj_cylinder([0,0,0],0.5,5,3);
  c2 = gobj_cylinder([1.25,0,0],0.5,5,3);
  c3 = gobj_cylinder([2.5,0,0],0.5,5,3);
  geom.objects = {b1, c1, c2, c3};
  grid = gridgen_scale( geom, 'axis', 3, 's_scal', 1/5 );
  plotgrid( grid, 'selcells', 'y>0' )
  plotsubd( grid, 'linewidth', 1, 'labels', 'off' )
  plotedg( grid, 'colors', {'k'}, 'labels', 'off', 'linewidth', 1 );

  4) Scale two blocks in a cylinder (only scaling sections with blocks).

  s1 = gobj_sphere();
  b1 = gobj_block(-1,1,-1,1,1.5,4.5);
  b2 = gobj_block(-1,1,-1,1,-3.5,-1.5,'B2');
  c1 = gobj_cylinder([0,0,-4],1.75,9,3);
  geom.objects = {s1, b1, b2, c1};
  grid = gridgen_scale( geom, 'axis', 3, 'p_scal', [-2.5, 3], 's_scal', [1/2, 1/4] );
  plotgrid( grid, 'selcells', 'y>0' )
  plotsubd( grid, 'linewidth', 1, 'labels', 'off' )
  plotedg( grid, 'colors', {'k'}, 'labels', 'off', 'linewidth', 1 );
See also