TITLE   'Percolation through a Concrete Block' 	         { sim231.pde }
SELECT     errlim=1e-4     ngrid=1      spectral_colors	
VARIABLES     phi     p	
DEFINITIONS
   L=1.0     visc=1e-3     k=1e-12
   p0=1e5     delp=1e3
   vx=dx( phi)     vy=dy( phi)     v=vector( vx, vy)     vm=magnitude( v)
EQUATIONS                  		
   phi:		div( grad( phi))=0
   p:		div( grad( p))=0
BOUNDARIES
region 'domain' start 'outer' (0,0)
   value( phi)=0   value( p)=p0  line to (L,0)  		{ Bottom }
   natural( phi)=0   natural( p)=0   line to (L,L) to (0,L) to (0,2/3*L)
   natural( phi)=k/visc*dx( p)   value( p)=delp+p0	{ Seeping window }
   line to (0,L/3)	
   natural( phi)=0   natural(p)=0 line to close
PLOTS
   contour( phi)     contour( p) painted     contour( vm) painted
   vector( v) norm     contour(div( v))     contour( curl( v))
   elevation( p) on 'outer'
END