{ BDRY_DENSITY.PDE }
{
This problem demonstrates the use of the MESH_DENSITY parameter to
control mesh density along a boundary.
The boundary of the inner region is forced to a grid spacing of 0.02
}
title 'Cell Size Control'
Variables
u
definitions
k = 1
u0 = 1-x^2-y^2
s = 2*3/4+5*2/4
b = 0.1
c = 0.02
equations
div(K*grad(u)) +s = 0
boundaries
Region 1
start(-1,-1)
value(u)=u0
line to (1,-1) to (1,1) to (-1,1) to close
Region 2
start(-b,-b)
mesh_density = 1/c { command inside the boundary path }
line to (b,-b) to (b,b) to (-b,b) to close
plots
grid(x,y)
contour(u) on region 2
end