!-------------------------------------------------------------------------------

!                      Code_Saturne version 2.0.4n!                      --------------------------

!     This file is part of the Code_Saturne Kernel, element of the
!     Code_Saturne CFD tool.

!     Copyright (C) 1998-2009 EDF S.A., France

!     contact: saturne-support@edf.fr

!     The Code_Saturne Kernel is free software; you can redistribute it
!     and/or modify it under the terms of the GNU General Public License
!     as published by the Free Software Foundation; either version 2 of
!     the License, or (at your option) any later version.

!     The Code_Saturne Kernel is distributed in the hope that it will be
!     useful, but WITHOUT ANY WARRANTY; without even the implied warranty
!     of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
!     GNU General Public License for more details.

!     You should have received a copy of the GNU General Public License
!     along with the Code_Saturne Kernel; if not, write to the
!     Free Software Foundation, Inc.,
!     51 Franklin St, Fifth Floor,
!     Boston, MA  02110-1301  USA

!-------------------------------------------------------------------------------

subroutine usray5 &
!================

 ( idbia0 , idbra0 ,                                              &
   ndim   , ncelet , ncel   , nfac   , nfabor , nfml   , nprfml , &
   nnod   , lndfac , lndfbr , ncelbr ,                            &
   nvar   , nscal  , iphas  , iappel ,                            &
   nideve , nrdeve , nituse , nrtuse ,                            &
   ifacel , ifabor , ifmfbr , ifmcel , iprfml , itypfb ,          &
   ipnfac , nodfac , ipnfbr , nodfbr , izfrdp ,                   &
   idevel , ituser , ia     ,                                     &
   xyzcen , surfac , surfbo , cdgfac , cdgfbo , xyznod , volume , &
   dt     , rtp    , rtpa   , propce , propfa , propfb ,          &
   coefa  , coefb  ,                                              &
   cofrua , cofrub ,                                              &
   w1     , w2     , w3     , w4     , w5     ,  w6     ,         &
   tparoi , qincid , flunet , xlam   , epa    , eps     ,  ck   , &
   rdevel , rtuser ,                                              &
   ra     )

!===============================================================================
!  Purpose:
!  --------

! User subroutine for input of radiative transfer parameters.

! This subroutine is calle twice. The first time is for boundary conditions.
! The second time is for the net radiation flux computation.


!  1. Fisrt call (IAPPEL = 1)
!  ==========================

!    1.1 Boundary conditions fot the radiative intensity (DO model)
!    --------------------------------------------------------------

!       The array COFRUA store the intensity for each boundary faces,
!         depending of the natur of the boundary (Dirichlet condition).
!       The intensity of radiation is defined as the rate of emitted
!         energy from unit surface area through unit solid angle.

!       For example:


! 1/ Gray wall: isotropic radiation field.
!                                    4
!                      eps.sig.tparoi         (1-eps).qincid
!        cofrua   =    --------------    +    --------------
!                            pi                     pi
!  wall intensity     wall emission           reflecting flux.

!     (eps=1: black wall; eps=0: reflecting wall)


! 2/ Free boundary: entering intensity is fixed to zero

!        cofrua   =   0.D0

!    (if the user has more information, he can do something better)



!    1.2 Boundary conditions fior the P-1 model
!    ------------------------------------------



!  2. Second call(IAPPEL = 2)
!  ==========================

!      The density of net radiation flux must calculated
!        consistently with the boundary conditions of the intensity.
!      The density of net flux is the balance between the radiative
!      emiting part of a boudary face (and not the reflecting one)
!      and the radiative absorbing part.

!      The provided example is consistently with the proposed boundary
!      conditions for the intensity.

!-------------------------------------------------------------------------------
! Arguments
!__________________.____._____.________________________________________________.
! name             !type!mode ! role                                           !
!__________________!____!_____!________________________________________________!
! idbia0           ! i  ! <-- ! number of first free position in ia            !
! idbra0           ! i  ! <-- ! number of first free position in ra            !
! ndim             ! i  ! <-- ! spatial dimension                              !
! ncelet           ! i  ! <-- ! number of extended (real + ghost) cells        !
! ncel             ! i  ! <-- ! number of cells                                !
! nfac             ! i  ! <-- ! number of interior faces                       !
! nfabor           ! i  ! <-- ! number of boundary faces                       !
! nfml             ! i  ! <-- ! number of families (group classes)             !
! nprfml           ! i  ! <-- ! number of properties per family (group class)  !
! nnod             ! i  ! <-- ! number of vertices                             !
! lndfac           ! i  ! <-- ! size of nodfac indexed array                   !
! lndfbr           ! i  ! <-- ! size of nodfbr indexed array                   !
! ncelbr           ! i  ! <-- ! number of cells with faces on boundary         !
! nvar             ! i  ! <-- ! total number of variables                      !
! nscal            ! i  ! <-- ! total number of scalars                        !
! iphas            ! i  ! <-- ! current phase number                           !
! iappel           ! i  ! <-- ! current subroutine call number                 !
! nideve, nrdeve   ! i  ! <-- ! sizes of idevel and rdevel arrays              !
! nituse, nrtuse   ! i  ! <-- ! sizes of ituser and rtuser arrays              !
! ifacel(2, nfac)  ! ia ! <-- ! interior faces -> cells connectivity           !
! ifabor(nfabor)   ! ia ! <-- ! boundary faces -> cells connectivity           !
! ifmfbr(nfabor)   ! ia ! <-- ! boundary face family numbers                   !
! ifmcel(ncelet)   ! ia ! <-- ! cell family numbers                            !
! iprfml           ! ia ! <-- ! property numbers per family                    !
!  (nfml, nprfml)  !    !     !                                                !
! itypfb           ! ia ! <-- ! boundary face types                            !
!  (nfabor, nphas) !    !     !                                                !
! ipnfac(nfac+1)   ! ia ! <-- ! interior faces -> vertices index (optional)    !
! nodfac(lndfac)   ! ia ! <-- ! interior faces -> vertices list (optional)     !
! ipnfbr(nfabor+1) ! ia ! <-- ! boundary faces -> vertices index (optional)    !
! nodfbr(lndfbr)   ! ia ! <-- ! boundary faces -> vertices list (optional)     !
! izfrdp(nfabor)   ! ia ! --> ! boundary faces -> zone number                  !
! idevel(nideve)   ! ia ! <-- ! integer work array for temporary developpement !
! ituser(nituse    ! ia ! <-- ! user-reserved integer work array               !
! ia(*)            ! ia ! --- ! main integer work array                        !
! xyzcen           ! ra ! <-- ! cell centers                                   !
!  (ndim, ncelet)  !    !     !                                                !
! surfac           ! ra ! <-- ! interior faces surface vectors                 !
!  (ndim, nfac)    !    !     !                                                !
! surfbo           ! ra ! <-- ! boundary faces surface vectors                 !
!  (ndim, nfavor)  !    !     !                                                !
! cdgfac           ! ra ! <-- ! interior faces centers of gravity              !
!  (ndim, nfac)    !    !     !                                                !
! cdgfbo           ! ra ! <-- ! boundary faces centers of gravity              !
!  (ndim, nfabor)  !    !     !                                                !
! xyznod           ! ra ! <-- ! vertex coordinates (optional)                  !
!  (ndim, nnod)    !    !     !                                                !
! volume(ncelet)   ! ra ! <-- ! cell volumes                                   !
! dt(ncelet)       ! ra ! <-- ! time step (per cell)                           !
! rtp, rtpa        ! ra ! <-- ! calculated variables at cell centers           !
!  (ncelet, *)     !    !     !  (at current and preceding time steps)         !
! propce(ncelet, *)! ra ! <-- ! physical properties at cell centers            !
! propfa(nfac, *)  ! ra ! <-- ! physical properties at interior face centers   !
! propfb(nfabor, *)! ra ! <-- ! physical properties at boundary face centers   !
! coefa, coefb     ! ra ! <-- ! boundary conditions                            !
!  (nfabor, *)     !    !     !                                                !
! cofrua, cofrub   ! ra ! --> ! boundary conditions for intensity or P-1 model !
!  (nfabor, *)     !    !     !                                                !
! w1,2,3,4,5,6     ! ra ! --- ! work arrays                                    !
!  (ncelet)        !    !     !                                                !
! tparoi(nfabor)   ! ra ! <-- ! inside current wall temperature (K)            !
! qincid(nfabor)   ! ra ! <-- ! radiative incident flux  (W/m2)                !
! flunet(nfabor)   ! ra ! --> ! net flux (W/m2)                                !
! xlamp(nfabor)    ! ra ! --> ! conductivity (W/m/K)                           !
! epap(nfabor)     ! ra ! --> ! thickness (m)                                  !
! epsp(nfabor)     ! ra ! --> ! emissivity (>0)                                !
! ck(ncelet)       ! ra ! <-- ! absoprtion coefficient                         !
! rdevel(nrdeve)   ! ra ! <-> ! real work array for temporary developpement    !
! rtuser(nituse)   ! ra ! <-- ! user-reserved real work array                  !
! ra(*)            ! ra ! --- ! main real work array                           !
!__________________!____!_____!________________________________________________!

!     Type: i (integer), r (real), s (string), a (array), l (logical),
!           and composite types (ex: ra real array)
!     mode: <-- input, --> output, <-> modifies data, --- work array
!===============================================================================

implicit none

!===============================================================================
! Common blocks
!===============================================================================

include "paramx.h"
include "numvar.h"
include "entsor.h"
include "optcal.h"
include "cstphy.h"
include "cstnum.h"
include "pointe.h"
include "parall.h"
include "period.h"
include "ppppar.h"
include "ppthch.h"
include "cpincl.h"
include "ppincl.h"
include "radiat.h"
include "ihmpre.h"

!===============================================================================

! Arguments

integer          idbia0 , idbra0
integer          ndim   , ncelet , ncel   , nfac   , nfabor
integer          nfml   , nprfml
integer          nnod   , lndfac , lndfbr , ncelbr
integer          nvar   , nscal  , iphas  , iappel
integer          nideve , nrdeve , nituse , nrtuse

integer          ifacel(2,nfac) , ifabor(nfabor)
integer          ifmfbr(nfabor) , ifmcel(ncelet)
integer          iprfml(nfml,nprfml) , itypfb(nfabor)
integer          ipnfac(nfac+1), nodfac(lndfac)
integer          ipnfbr(nfabor+1), nodfbr(lndfbr),izfrdp(nfabor)
integer          idevel(nideve), ituser(nituse), ia(*)

double precision xyzcen(ndim,ncelet)
double precision surfac(ndim,nfac), surfbo(ndim,nfabor)
double precision cdgfac(ndim,nfac), cdgfbo(ndim,nfabor)
double precision xyznod(ndim,nnod), volume(ncelet)
double precision dt(ncelet), rtp(ncelet,*), rtpa(ncelet,*)
double precision propce(ncelet,*)
double precision propfa(nfac,*), propfb(nfabor,*)
double precision coefa(nfabor,*), coefb(nfabor,*)

double precision cofrua(nfabor), cofrub(nfabor)

double precision w1(ncelet), w2(ncelet), w3(ncelet)
double precision w4(ncelet), w5(ncelet), w6(ncelet)

double precision tparoi(nfabor), qincid(nfabor)
double precision xlam(nfabor), epa(nfabor)
double precision eps(nfabor), flunet(nfabor)
double precision ck(ncelet)

double precision rdevel(nrdeve), rtuser(nrtuse), ra(*)


! Local variables

integer          idebia , idebra , ifac, iok
double precision unspi, xit, distbf

!===============================================================================

!===============================================================================
! 0 - Initialization
!===============================================================================

idebia = idbia0
idebra = idbra0

! Stop indicator (forgotten boundary faces)
iok = 0

unspi = 1.d0/pi

!==============================================================================
!  1. First call
!  =============
!===============================================================================

if (iappel.eq.1) then


!===============================================================================
!  1.1 - Boundary conditions:
!        DO model: COFRUA msut be filled with the intensity
!        P-1 model: COFRUA and COFRUB msut be filled
!      The provided examples are sufficient in most of cases.
!===============================================================================




!      A - DO model
!      ^^^^^^^^^^^^




  if (iirayo.eq.1) then

    do ifac = 1,nfabor

!      1.1.1 - Symmetry :
!              ----------
!          Reflecting boundary conditions ( EPS=0 )
!          ----------------------------------------

      if (itypfb(ifac).eq.isymet) then

        cofrua(ifac) = qincid(ifac) * unspi


!      1.1.2 - Inlet/Outlet face: entering intensity fixed to zero
!              (WARNING: the treatment is different from than of P-1 model)
!          -------------------------------------------------

      else if (itypfb(ifac).eq.ientre                             &
          .or. itypfb(ifac).eq.isolib) then

        cofrua(ifac) = epzero


!      1.1.3. - Wall boundary face: calculaed intensity
!               ---------------------------------------

      else if (itypfb(ifac).eq.iparoi                             &
          .or. itypfb(ifac).eq.iparug) then

        cofrua(ifac)  = eps(ifac)*stephn*(tparoi(ifac)**4)*unspi  &
                          + (1.d0-eps(ifac))* qincid(ifac)*unspi

      else

!      1.1.4 - Stop if there are forgotten faces
!              ---------------------------------

!           ==============================================

!             Don't skip this test

!           ==============================================

        write (nfecra,1000) ifac,izfrdp(ifac),itypfb(ifac)
        iok = iok + 1
      endif

    enddo




!   B - P-1 model
!   ^^^^^^^^^^^^^





  else if (iirayo.eq.2) then

    do ifac = 1,nfabor

!      1.1.1 - Symmetry or reflecting wall (EPS = 0) :
!              zero flux
!              ----------------------------------------

      if (itypfb(ifac).eq.isymet     .or.                         &
         ((itypfb(ifac).eq.iparoi.or.                             &
           itypfb(ifac).eq.iparug).and.eps(ifac).eq.0d0)) then

        cofrua(ifac) = 0.d0
        cofrub(ifac) = 1.d0


!      1.1.2 - Inlet/Outlet faces: zero flux
!              (WARNING: the treatment is different from than of DO model)
!              ----------------------------------------------------------

      else if (itypfb(ifac).eq.ientre                             &
          .or. itypfb(ifac).eq.isolib) then

        cofrua(ifac) = 0.d0
        cofrub(ifac) = 1.d0


!      1.1.3 - Wall boundary faces
!              -------------------

      else if (itypfb(ifac).eq.iparoi .or.                        &
               itypfb(ifac).eq.iparug ) then

        distbf = ra(idistb-1+ifac)

        xit = 1.5d0 *distbf *ck(ifabor(ifac))                     &
            * (2.d0 /(2.d0-eps(ifac)) -1.d0)

        cofrub(ifac) = 1.d0 / (1.d0 + xit)
        cofrua(ifac) = xit * tparoi(ifac)**4 * cofrub(ifac)

      else

!      1.1.4 - Stop if there are forgotten faces
!              ---------------------------------

!           ==============================================

!             Don't skip this test

!           ==============================================

        write (nfecra,1000) ifac,izfrdp(ifac),itypfb(ifac)
      iok = iok + 1
    endif

  enddo

  endif

  if (iok.ne.0) then
    write (nfecra,1100) iphas
    call csexit (1)
    !==========
  endif

!===============================================================================
!  2 - Second call
!  ================
!===============================================================================

else if (iappel.eq.2) then

!===============================================================================
!  2.1 - Net flux dendity for the boundary faces
!      The provided examples are sufficient in most of cases.
!===============================================================================

!    If the boundary conditions given above have been modified
!      it is necessary to change the way in which density is calculated from
!      the net radiative flux consistently.
!    The rule is:
!      the density of net flux is a balance between the emitting energy from a
!      boundary face (and not the reflecting energy) and the absorbing radiative
!      energy. Therefore if a wall heats the fluid by radiative transfer, the
!      net flux is negative


  do ifac = 1,nfabor

    if (itypfb(ifac).eq.iparoi .or.                               &
        itypfb(ifac).eq.iparug) then

!      2.1.1 - Wall faces
!              ----------

      flunet(ifac) =                                              &
      eps(ifac) *(qincid(ifac) - stephn*tparoi(ifac)**4)


!      2.1.2 - Symmetry :
!              ----------

    else if (itypfb(ifac).eq.isymet) then

      flunet(ifac)= zero


!      2.1.3 - Inlet/Outlet
!              ------------

    else if (itypfb(ifac).eq.ientre                               &
        .or. itypfb(ifac).eq.isolib) then

      if (iirayo.eq.1) then

      flunet(ifac)= qincid(ifac) -pi*cofrua(ifac)

      else if (iirayo.eq.2) then

        flunet(ifac)= 0.d0

      endif


!      2.1.4 - Stop if there are forgotten faces
!              ---------------------------------
    else

!           ==============================================

!             Don't skip this test

!           ==============================================

      write (nfecra,2000) ifac,izfrdp(ifac),itypfb(ifac)
      iok = iok + 1

    endif

  enddo


  if (iok.ne.0) then
    write (nfecra,2100) iphas
    call csexit (1)
    !==========
  endif


endif

! -------
! FORMATS
! -------

 1000 format(                                                           &
'@                                                            ',/,&
'@                                                            ',/,&
'@                                                            ',/,&
'@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@',/,&
'@                                                            ',/,&
'@ @@ WARNING: Radiative transfer (usray5)                    ',/,&
'@    ========                                                ',/,&
'@              Boundary conditions non inquiries             ',/,&
'@                                                            ',/,&
'@    Face = ',I10   ,' Zone = ',I10   ,' Nature = ',I10         )

 1100 format(                                                           &
'@                                                            ',/,&
'@                                                            ',/,&
'@                                                            ',/,&
'@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@',/,&
'@                                                            ',/,&
'@ @@ WARNING: Radiative transfer (usray5)                    ',/,&
'@    ========                                                ',/,&
'@    Boundary conditions are unknown for some faces          ',/,&
'@     (Phase ',I10   ,')                                     ',/,&
'@                                                            ',/,&
'@    The calculation stops.                                  ',/,&
'@                                                            ',/,&
'@    Please verify subroutine usray5.                        ',/, &
'@                                                            ',/,&
'@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@',/,&
'@                                                            ',/)

 2000 format(                                                           &
'@                                                            ',/,&
'@                                                            ',/,&
'@                                                            ',/,&
'@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@',/,&
'@                                                            ',/,&
'@ @@ WARNING: Radiative transfer (usray5)                    ',/,&
'@    ========                                                ',/,&
'@              Net flux calculation non inquiries            ',/,&
'@                                                            ',/,&
'@    Face = ',I10   ,' Zone = ',I10   ,' Nature = ',I10         )

 2100 format(                                                           &
'@                                                            ',/,&
'@                                                            ',/,&
'@                                                            ',/,&
'@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@',/,&
'@                                                            ',/,&
'@ @@ WARNING: Radiative transfer (usray5)                    ',/,&
'@    ========                                                ',/,&
'@    Net radiation flux is unknown for some faces            ',/,&
'@     (Phase ',I10   ,')                                     ',/,&
'@                                                            ',/,&
'@    The calculation stops.                                  ',/,&
'@                                                            ',/,&
'@    Please verify subroutine usray5.                        ',/, &
'@                                                            ',/,&
'@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@',/,&
'@                                                            ',/)



