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

!                      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 usvima &
!================

 ( idbia0 , idbra0 ,                                              &
   ndim   , ncelet , ncel   , nfac   , nfabor , nfml   , nprfml , &
   nnod   , lndfac , lndfbr , ncelbr ,                            &
   nvar   , nscal  ,                                              &
   nideve , nrdeve , nituse , nrtuse ,                            &
   ifacel , ifabor , ifmfbr , ifmcel , iprfml ,                   &
   ipnfac , nodfac , ipnfbr , nodfbr ,                            &
   idevel , ituser , ia     ,                                     &
   xyzcen , surfac , surfbo , cdgfac , cdgfbo , xyznod , volume , &
   dt     , rtp    , rtpa   , propce , propfa , propfb ,          &
   coefa  , coefb  ,                                              &
   viscmx , viscmy , viscmz ,                                     &
   w1     , w2     , w3     , w4     ,                            &
   w5     , w6     , w7     , w8     ,                            &
   rdevel , rtuser , ra     )

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

!    User subroutine dedicated the use of ALE (Arbitrary Lagrangian Eulerian Method) :
!                 fills mesh viscosity arrays.


!    This subroutine is called at the beginning of each time step.

!    Here one can modify mesh viscosity value to prevent cells and nodes
!    from huge displacements in awkward areas, such as boundary layer for example.

!    IF variable IORTVM = 0, mesh viscosity modeling is isotropic therefore VISCMX
!    array only needs to be filled.
!    IF variable IORTVM = 1, mesh viscosity modeling is orthotropic therefore
!    all arrays VISCMX, VISCMY and VISCMZ need to be filled.

!    Note that VISCMX, VISCMY and VISCMZ arrays are initialized at the first time step to the value of 1.

! Cells identification
! ====================

! Cells may be identified using the 'getcel' subroutine.
! The syntax of this subroutine is described in the 'usclim' subroutine,
! but a more thorough description can be found in the user guide.

!-------------------------------------------------------------------------------
! 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                        !
! nphas            ! i  ! <-- ! number of phases                               !
! 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)  !    !     !                                                !
! 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)     !
! 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, *)     !    !     !                                                !
! viscmx(ncelet)    ! ra ! <-- ! mesh viscosity in X direction                 !
! viscmy(ncelet)    ! ra ! <-- ! mesh viscosity in Y direction                 !
! viscmz(ncelet)    ! ra ! <-- ! mesh viscosity in Z direction                 !
! w1,2,3,4,5,6     ! ra ! --- ! work arrays                                    !
!  (ncelet)        !    !     !  (computation of pressure gradient)            !
! 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 "dimfbr.h"
include "paramx.h"
include "pointe.h"
include "numvar.h"
include "optcal.h"
include "cstphy.h"
include "entsor.h"
include "parall.h"
include "period.h"
include "albase.h"

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

! Arguments

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

integer          ifacel(2,nfac) , ifabor(nfabor)
integer          ifmfbr(nfabor) , ifmcel(ncelet)
integer          iprfml(nfml,nprfml)
integer          ipnfac(nfac+1), nodfac(lndfac)
integer          ipnfbr(nfabor+1), nodfbr(lndfbr)
integer          idevel(nideve), ituser(nituse)
integer          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(ndimfb,*)
double precision coefa(ndimfb,*), coefb(ndimfb,*)
double precision viscmx(ncelet), viscmy(ncelet), viscmz(ncelet)
double precision w1(ncelet),w2(ncelet),w3(ncelet),w4(ncelet)
double precision w5(ncelet),w6(ncelet),w7(ncelet),w8(ncelet)
double precision rdevel(nrdeve), rtuser(nrtuse), ra(*)

! Local variables

integer          idebia, idebra
integer          iel
double precision rad, xr2, xcen, ycen, zcen

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


idebia = idbia0
idebra = idbra0

!===============================================================================
!  1. Example :
!       One gives a huge mesh viscosity value to the cells included in a circle
!       with a radius 'rad' and a center '(xcen, ycen, zcen)'

!     In general it appears quite much easier to fill mesh viscosity arrays at
!     the beginning of the calculations basing on the initial geometry.

if (ntcabs.eq.0) then
  rad = (1.d-3)**2
  xcen  = 1.d0
  ycen  = 0.d0
  zcen  = 0.d0

  do iel = 1, ncel
    xr2 = (xyzcen(1,iel)-xcen)**2 + (xyzcen(2,iel)-ycen)**2       &
         + (xyzcen(3,iel)-zcen)**2
    if (xr2.lt.rad) viscmx(iel) = 1.d10
  enddo

! 2. In case of orthotropic mesh viscosity modeling one can choose
!    to submit nodes to a lower stress in Z direction
  if (iortvm.eq.1) then
    do iel = 1, ncel
      viscmy(iel) = viscmx(iel)
      viscmz(iel) = 1.d0
    enddo
  endif

endif

!----
! Formats
!----

!----
! End
!----

return
