photon use
  p
  parphi
  20 1
 
  msg radial (ie vertical) scale has been enlarged 20-fold
  msg velocity vectors
  vec x 1 sh;pause;vec off;red
  msg effective-viscosity contours
  con enut x 1 fi;0.1;pause;con off;red
  msg w1 contours
  con w1 x 1 fi;0.1;pause;con off;red
  msg temperature contours
  con temperature x 1 fi;0.1;pause;con off;red
  enduse
 
    GROUP 1. Run title and other preliminaries
TEXT(Pipe Flow M-Length Turb Model;Para
TITLE
  DISPLAY
  The problem considered is turbulent flow in a smooth-walled pipe,
  with a wall temperature at a uniform value below that of the
  entering fluid.
  The calculation is continued to a distance of 30 diameters from
  the entrance, to enable the velocity and temperature profiles to
  attain unchanging shapes.
  The Prandtl mixing-length model is used, with Nikuradze's formula
  for the length scale:
      2(Lm/D) = 0.14 - 0.08(2y/D)**2 - 0.06(2y/D)**4
  where y is the normal distance from the channel wall.
 
                          Wall at temperature TWALL
             /////////////////////////////////////////////////////
  Constant   -----------------------------------------------------
  specified --->                                               ->
  mass-flux,--->                                               -->
  velocity  --->                                               --->
  and        - - - - - - - - - - -Symmetry line- - - - - - - - - -
  temperature ^
              |-------> z-direction
  ENDDIS
 
REAL(PLEN,DIAM,WIN,REYNO,RAD,TIN,TWALL,EWAL,AK,RAD3)
REYNO=4.E5;DIAM=1.0;WIN=1.0;TIN=1.;TWALL=0.;AK=.41;EWAL=8.6
mesga(Reynolds Number is :reyno:  OK? If not, insert desired value
readvdu(reyno,real,reyno)
reyno
    GROUP 3. X-direction grid specification
CARTES=F;XULAST=0.1
    GROUP 4. Y-direction grid specification
NY=30;RAD=0.5*DIAM;GRDPWR(Y,NY,RAD,0.75)
    GROUP 5. Z-direction grid specification
PARAB=T;NZ=40;PLEN=30.*DIAM;GRDPWR(Z,NZ,PLEN,1.0)
    GROUP 7. Variables stored, solved & named
SOLVE(P1,V1,W1);STORE(ENUT)
NAME(H1)=TEMP;SOLVE(TEMP);STORE(LEN1)
    GROUP 8. Terms (in differential equations) & devices
TERMS(TEMP,N,Y,Y,Y,Y,Y)
    GROUP 9. Properties of the medium (or media)
ENUL=WIN*DIAM/REYNO;PRT(TEMP)=0.86;PRNDTL(TEMP)=0.7
  ** Use Nikuradse's formula noting that wall is at north boundary
     at distance RAD from the centre-line...
ENUT=MIXLEN;RAD3=RAD**3
EL1=NIKURPIP;EL1A=.14*RAD;EL1B=-0.08/RAD;EL1C=-0.06/RAD3
    GROUP 11. Initialization of variable or porosity fields
FIINIT(W1)=WIN;FIINIT(TEMP)=TIN
    GROUP 13. Boundary conditions and special sources
  ** North-Wall Boundary
WALL(WFUN,NORTH,1,1,NY,NY,1,NZ,1,1);COVAL(WFUN,TEMP,LOGLAW,TWALL)
  ** Inlet Boundary
INLET(IN,LOW,1,1,1,NY,1,1,1,1);VALUE(IN,P1,WIN);VALUE(IN,W1,WIN)
VALUE(IN,TEMP,TIN)
    GROUP 16. Termination of iterations
LITHYD=20;SELREF=T;RESFAC=0.01
    GROUP 17. Under-relaxation devices
RELAX(ENUT,LINRLX,0.25)
    GROUP 19. Data communicated by SATELLITE to GROUND
DWDY=T
    GROUP 21. Print-out of variables
OUTPUT(TEMP,Y,Y,Y,N,Y,Y)
    GROUP 22. Monitor print-out
IZMON=1;IYMON=27;ITABL=1;NPLT=1;NPRMON=1
 
    GROUP 23. Field print-out and plot control
PATCH(IZEQNZ,PROFIL,1,1,1,NY,NZ,NZ,1,1)
PLOT(IZEQNZ,W1,0.0,0.0);PLOT(IZEQNZ,LEN1,0.0,0.0)
PATCH(LONGPLOT,PROFIL,1,NZ,NY,NY,3,NZ,1,1)
PLOT(LONGPLOT,W1,0.0,0.0);PLOT(LONGPLOT,TEMP,TWALL,TIN)
PATCH(LONGPLT2,PROFIL,1,1,1,1,3,NZ,1,1)
PLOT(LONGPLT2,W1,0.0,0.0);PLOT(LONGPLT2,TEMP,TWALL,TIN)
    GROUP 24. Dumps for restarts
  ** create file parphi or parada for PHOTON viewing
WALPRN=T;UWATCH=T;TSTSWP=LITHYD-1;IDISPA=2
mesg(Use low-Reynolds-Number modification? (y/n)
READVDU(ANS,CHAR,N)
IF(:ANS:.EQ.Y) THEN
mesg(enter 6 for fourth-power decay of turbulent viscosity or
mesg(      9 for complete cut-off at turb/lam = 20
READVDU(IENUTA,INT,0)
IF(IENUTA.EQ.9) THEN
 ENUTA=0.05
ENDIF
IF(IENUTA.EQ.6) THEN
 ENUTA=0.2;ENUTB=4.0
ENDIF
RELAX(ENUT,LINRLX,0.1)
ENDIF
IENUTA