GROUP 1. Run title
L(W900)
TEXT(STRATIFIED FLOW,  CASE 2 PIPE :     W901
TITLE
    GROUP 13. Boundary conditions and special sources
  ** Force along pipe resulting from gravity at right angles
    The next three entries introduce a momentum source into
    the equation for the second-phase velocity which is
    equal to the difference of hydrostatic pressure caused
    by a difference in volume fraction from one computational
    cell to the next.
    HGSOA is simply an iteration-cut-off criterion, used in a
    sequence which calculates the cross-sectional area of the
    water-filled part of the pipe from the volume fraction.
    BUOYA carries the gravitational acceleration; HGSOB
    carries the density difference; and YVLAST represents the
    pipe radius.
PATCH(LATG,CELL,1,NX,1,1,1,1,1,LSTEP)
COVAL(LATG,2U,FIXFLU,GRND10)
HGSOA=0.0001;BUOYA=9.81;HGSOB=RHO1-RHO2;YVLAST=0.5;IROTAA=3