```
TALK=T;RUN(1,1)
photon use
p;;;;;

msg The grid
gr z 1 ;pause;gr off;red; gr ou z 1
con radx z 1 fi;0.001;pause;con off;red
con rady z 1 fi;0.001;pause;con off;red
msg Contours of H1
con h1 z 1 fi;0.001;pause;con off;red
enduse
DISPLAY
Radiative heat transfer takes place in a 2D box, which
contains a semi-transparent medium at rest.

The east and north walls are at a temperature TCOLD;
the west and south  walls have temperatures THOT1 in their
first halves and THOT2 in their second halves.

THOT2 > THOT1 > TCOLD.

The solved-for variables are temperature and two radiation
quantities, namely the composite fluxes in the X and Y
directions, with the asumptions of the four-flux model.
ENDDIS
************************************************************
Group 1. Run Title and Number
************************************************************
************************************************************

TEXT(2D Radiant Heat Transfer In A Box       )

************************************************************
************************************************************

IRUNN = 1 ;LIBREF = 14
************************************************************
Group 2. Time dependence
************************************************************
Group 3. X-Direction Grid Spacing
CARTES = T
NX = 10
XULAST =1.
XFRAC(1)=0.1 ;XFRAC(3)=0.3
XFRAC(5)=0.5 ;XFRAC(7)=0.7
XFRAC(9)=0.9
************************************************************
Group 4. Y-Direction Grid Spacing
NY = 10
YVLAST =1.
YFRAC(1)=0.1 ;YFRAC(3)=0.3
YFRAC(5)=0.5 ;YFRAC(7)=0.7
YFRAC(9)=0.9
************************************************************
Group 5. Z-Direction Grid Spacing
PARAB = F
NZ = 1
ZWLAST =1.
ZFRAC(1)=1.
************************************************************
Group 6. Body-Fitted Coordinates
************************************************************
Group 7. Variables: STOREd,SOLVEd,NAMEd
ONEPHS = T
* Y in SOLUTN argument list denotes:
* 1-stored 2-solved 3-whole-field
* 4-point-by-point 5-explicit 6-harmonic averaging
SOLUTN(H1,Y,Y,N,N,N,Y)
************************************************************
Group 8. Terms & Devices
* Y in TERMS argument list denotes:
* 1-built-in source 2-convection 3-diffusion 4-transient
* 5-first phase variable 6-interphase transport
TERMS(H1,N,N,Y,Y,Y,Y)
DIFCUT =0.5 ;ZDIFAC =1.
GALA = F ;ADDDIF = F
ISOLX = -1 ;ISOLY = -1 ;ISOLZ = -1
************************************************************
Group 9. Properties used if PRPS is not
stored, and where PRPS = -1.0 if it is!
RHO1 =1. ;TMP1 = GRND2
EL1 =0.
TSURR =0. ;TEMP0 =0.
PRESS0 =0.
DVO1DT =0. ;DRH1DP =0.
TMP1A =0. ;TMP1B =1.
TMP1C =0.
TMP2A =0. ;TMP2B =0.
TMP2C =0.
EMISS =0. ;SCATT =0.
ENUL =1.0E-05 ;ENUT =0.
CP1 =1. ;CP2 =1.
************************************************************
Group 10.Inter-Phase Transfer Processes
************************************************************
Group 11.Initial field variables (PHIs)
No PATCHes yet used for this Group
FSWEEP = 1
NAMFI =CHAM
************************************************************
Group 12. Patchwise adjustment of terms
Patches for this group are printed with those
for Group 13.
Their names begin either with GP12 or &
************************************************************
Group 13. Boundary & Special Sources

PATCH(RADISO ,FREEVL, 0, 0, 0, 0, 0, 0, 1, 1)
COVAL(RADISO ,H1 , GRND1 , GRND1 )

PATCH(HOTW1R ,WEST , 1, 1, 1, 5, 1, 1, 1, 1)

PATCH(HOTW2R ,WEST , 1, 1, 6, 10, 1, 1, 1, 1)

PATCH(COLDER ,EAST , 10, 10, 1, 10, 1, 1, 1, 1)

PATCH(HOTS1R ,SOUTH , 1, 5, 1, 1, 1, 1, 1, 1)

PATCH(HOTS2R ,SOUTH , 6, 10, 1, 1, 1, 1, 1, 1)

PATCH(COLDNR ,NORTH , 1, 10, 10, 10, 1, 1, 1, 1)

PATCH(HOTW1H ,WEST , 1, 1, 1, 5, 1, 1, 1, 1)
COVAL(HOTW1H ,H1 ,1. ,666. )

PATCH(HOTW2H ,WEST , 1, 1, 6, 10, 1, 1, 1, 1)
COVAL(HOTW2H ,H1 ,1. ,777. )

PATCH(COLDEH ,EAST , 10, 10, 1, 10, 1, 1, 1, 1)
COVAL(COLDEH ,H1 ,1. ,293. )

PATCH(HOTS1H ,SOUTH , 1, 10, 1, 1, 1, 1, 1, 1)
COVAL(HOTS1H ,H1 ,1. ,666. )

PATCH(HOTS2H ,SOUTH , 6, 10, 1, 1, 1, 1, 1, 1)
COVAL(HOTS2H ,H1 ,1. ,777. )

PATCH(COLDNH ,NORTH , 1, 10, 10, 10, 1, 1, 1, 1)
COVAL(COLDNH ,H1 ,1. ,293. )
XCYCLE = F
EGWF = T
WALLCO = GRND2
************************************************************
Group 14. Downstream Pressure For PARAB
************************************************************
Group 15. Terminate Sweeps
LSWEEP = 30 ;ISWC1 = 1
LITHYD = 1 ;LITFLX = 1 ;LITC = 1 ;ITHC1 = 1
SELREF = T
RESFAC =0.1
************************************************************
Group 16. Terminate Iterations
************************************************************
Group 17. Relaxation
RELAX(H1,FALSDT,1.0E-02)
OVRRLX =0.
EXPERT = F ;NNORSL = F
************************************************************
Group 18. Limits
VARMAX(H1)=1.0E+10 ;VARMIN(H1)=-1.0E+10
************************************************************
Group 19. Data transmitted to GROUND
PARSOL = F
ISG62 = 1
************************************************************
Group 20. Preliminary Printout
************************************************************
Group 21. Print-out of Variables
INIFLD = F ;SUBWGR = F
* Y in OUTPUT argument list denotes:
* 1-field 2-correction-eq. monitor 3-selective dumping
* 4-whole-field residual 5-spot-value table 6-residual table
OUTPUT(H1,Y,Y,Y,Y,Y,Y)
************************************************************
Group 22. Monitor Print-Out
IXMON = 5 ;IYMON = 5 ;IZMON = 1
NPRMON = 100000 ;NPRMNT = 1 ;TSTSWP = -1
UWATCH = T ;USTEER = T
HIGHLO = F
************************************************************
Group 23.Field Print-Out & Plot Control
NPRINT = 100000 ;NUMCLS = 5
NXPRIN = 2 ;IXPRF = 1 ;IXPRL = 10000
NYPRIN = 2 ;IYPRF = 1 ;IYPRL = 10000
IPLTF = 1 ;IPLTL = -1 ;NPLT = 2
ISWPRF = 1 ;ISWPRL = 100000
ITABL = 3 ;IPROF = 1
ABSIZ =0.5 ;ORSIZ =0.4
NTZPRF = 1 ;NCOLPF = 50
ICHR = 2 ;NCOLCO = 45 ;NROWCO = 20

PATCH(DOMAIN ,CONTUR, 1, 10, 1, 10, 1, 1, 1, 1)
PLOT(DOMAIN ,H1 ,0. ,10. )