#immersol)
#declare
TEXT(IMMERSOL- 1D fixed flux through domain :208
#cls
TITLE
  DISPLAY
  
  Radiative transfer occurs through a wide slab-shaped medium,
  through one boundary of which radiant heat enters. The other
  boundary is held at a fixed temperature.
  
  The heat input to the wall is transferred to the first wall by 
  radiation and conduction across the space between them.
  
  This space contains a gas of finite absorptivity.
  
  The question to be answered is: what will be the temperature of
  the first boundary, if the conductivity is set to zero?
  
  
  
  ENDDIS
  **************************************************************
   PHOTON USE
   AUTOPLOT 
   FILE
   PHI 5
 
   CL;DA 1 TEM1;DA 1 T3;COL3 1;BLB4 2;REDR
   MSG    Temperature and T3 profiles.
   ENDUSE
  **************************************************************
#direct
MESG(  ENTER optical thickness Kr*Wg (default 1.):
READVDU(OPTHI,REAL,1.0)
WGAP = 1.0;  KGAS= 0.0258
KROSS= OPTHI/WGAP;  SCATT= 0.0;  EMISS= KROSS-SCATT
FIINIT(EMIS)=EMISS; FIINIT(SCAT)=SCATT
SOLVE(TEM1)
#geom2
#radflux
TERMS(TEM1,N,N,Y,N,Y,N)
    *** Set diffusivities for TEM1 and T3 (i.e. PRNDTL() must be
        set to -Value). NOTE! value of diffusivity for T3 in a gas
        is not important (correct value is calculated by EARTH);
PRNDTL(TEM1)= 1.e10  
INIADD= F;  FIINIT(TEM1)= 500.;FIINIT(T3)= 500.
    *** Set radiative heat flux through the domain:
COVAL(IMSWL1,T3,FIXFLU,1000.); COVAL(IMSWL2,T3,FIXVAL,500.)
LSWEEP= 50; SELREF=F; RESREF(T3)= 1.E-3
IXMON=NX/2+1;IYMON=NY/2+1;IZMON=NZ/2+1;
NXPRIN=1; NYPRIN=1; NZPRIN=1
OUTPUT(LTLS,N,N,N,N,N,N); OUTPUT(WDIS,N,N,N,N,N,N)
  
VARMIN(T3)=FIINIT(T3)*0.33;  VARMAX(T3)=FIINIT(T3)*3.0
VARMIN(TEM1)=FIINIT(TEM1)*0.33;  VARMAX(TEM1)=FIINIT(TEM1)*3.0