L(246)
    GROUP 1. Run title and other preliminaries
TEXT(Pipe With Internal Restriction   
TITLE
  This run analyses the flow in a pipe with an orifice at
  quarter-length. The pipe wall is at a constant temperature.
  Cylindrical-polar coordinates are used in the y-z plane:
  y being in the radial direction; z being along the axis.
  Interesting variants include changes to: the size and position
  of the orifice; entry values of scalar quantities; and the
  temperature of restricting plate.
INLET(IN,LOW,1,1,1,NY,1,1,1,1)
VALUE(IN,P1,0.1); VALUE(IN,W1,0.1)
  ** Represent constriction by fixing W1 to zero...
PATCH(RESTRIC,HIGH,1,1,NY/2+1,NY,NZ/4,NZ/4,1,1)
COVAL(RESTRIC,W1,FIXVAL,0.0)
NYPRIN=1; NZPRIN=1; IYPRF=NY/2-1; IZPRF=NZ/4-1; IZPRL=NZ/4+3