GROUP 1. Run title and other preliminaries
TEXT(Pipe Flow With Axial Free Convec 
TITLE
  DISPLAY
    An extra momentum source is added to the axial momentum
  equation to represent a buoyancy force, in order to simulate
  free convection in a pipe flow.
 
                     . - .
                   /       \
                  |         |
                  |\       /|
    Axial    g    |         | ^
    buoyancy |    |         | |
    force    v    |         | |z
    acts as       |         |
    momentum      |  . - .  |
    source        |/       \|
                  |  ^   ^  |  Fixed mass,
                   \ |   | /---momentum and
                     | - |     enthalpy flux
                        -->    into inlet
                        r
  ENDDIS
 
    GROUP 3. X-direction grid specification
CARTES=F
 
    GROUP 4. Y-direction grid specification
   *** 20 grid cells are used in y-direction to cover
       an extent of 0.01 m
IREGY=1; GRDPWR(Y,20,0.01,1.0)
 
    GROUP 5. Z-direction grid specification
   *** The flow is parabolic
PARAB=T; IREGZ=1; GRDPWR(Z,20,0.20,1.0)
 
    GROUP 7. Variables stored, solved & named
#solvel
SOLVE(H1)
 
    GROUP 9. Properties of the medium (or media)
  Fluid is air at STP (standard temperature and pressure)
#fluidmat
setprps(1,air20)
PRNDTL(H1)=0.7
    GROUP 13. Boundary conditions and special sources
   1. Inlet boundary: uniform velocity
 
INLET(UNIFORM,LOW,#1,#1,#1,#NREGY,#1,#1,1,1)
VALUE(UNIFORM,P1,0.1); VALUE(UNIFORM,W1,0.1);VALUE(UNIFORM,H1,0.0)
 
   2. Wall boundary: constant temperature (and therefore enthalpy)
 
WALL (PIPE,NORTH,#1,#1,#NREGY,#NREGY,#1,#NREGZ,1,1)
COVAL(PIPE,W1,1.0,0.0); COVAL(PIPE,H1,1.0,1.0e3)
 
   3. Buoyancy source
 
#gravity
  gravity acts in the negative z direction; reference enthalpy = 0
gravdir=6; href=0.0
#bouss
 
    GROUP 16. Termination of iterations
LITHYD=30; TSTSWP=5
 
    GROUP 22. Spot-value print-out
NPLT=1; NPRMON=30; IYMON=NY/4
 
    GROUP 23. Field print-out and plot control
NYPRIN=2; NZPRIN=10
   *** Plot exit profile of velocity and temperature
PATCH(EXIT,PROFIL,1,1,1,NY,NZ,NZ,1,1)
PLOT(EXIT,W1,0.0,0.0);PLOT(EXIT,H1,0.0,0.0)
  dump fields at every z-step to parphi
IDISPA=1
  PHOTON USE
  p
  parphi
  10 1
 
  up z
  gr ou x 1
  msg radial scal is enlarged by factor of 10
  msg velocity vectors
  vec x 1 sh
  pause
  msg enthalpy contours
  con h1 x 1 fi;0.001
  pause
  msg presure contours
  con p1 x 1 fi;0.001
  pause
  msg velocity contours
  con w1 x 1 fi;0.001
  ENDUSE