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

!                      Code_Saturne version 4.0-alpha
!                      --------------------------
! This file is part of Code_Saturne, a general-purpose CFD tool.
!
! Copyright (C) 1998-2015 EDF S.A.
!
! This program 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.
!
! This program 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
! this program; if not, write to the Free Software Foundation, Inc., 51 Franklin
! Street, Fifth Floor, Boston, MA 02110-1301, USA.

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

!===============================================================================
! Function:
! ---------

!> \file cs_user_boundary_conditions_ale.f90
!>
!> \brief User subroutine dedicated the use of ALE (Arbitrary Lagrangian
!> Eulerian) Method:
!>  - Fills boundary conditions (ialtyb, icodcl, rcodcl) for mesh velocity.
!>  - This subroutine also enables one to fix displacement on nodes.
!>
!-------------------------------------------------------------------------------

!-------------------------------------------------------------------------------
! Arguments
!______________________________________________________________________________.
!  mode           name          role
!______________________________________________________________________________!
!> \param[in]     itrale        number of iterations for ALE method
!> \param[in]     nvar          total number of variables
!> \param[in]     nscal         total number of scalars
!> \param[out]    icodcl        boundary condition code:
!>                               - 1 Dirichlet
!>                               - 2 Radiative outlet
!>                               - 3 Neumann
!>                               - 4 sliding and
!>                                 \f$ \vect{u} \cdot \vect{n} = 0 \f$
!>                               - 5 smooth wall and
!>                                 \f$ \vect{u} \cdot \vect{n} = 0 \f$
!>                               - 6 rough wall and
!>                                 \f$ \vect{u} \cdot \vect{n} = 0 \f$
!>                               - 9 free inlet/outlet
!>                                 (input mass flux blocked to 0)
!> \param[in,out] itypfb        boundary face types
!> \param[out]    ialtyb        boundary face types for mesh velocity
!> \param[in]     impale        indicator for fixed node displacement
!> \param[in]     dt            time step (per cell)
!> \param[in,out] rcodcl        boundary condition values:
!>                               - rcodcl(1) value of the dirichlet
!>                               - rcodcl(2) value of the exterior exchange
!>                                 coefficient (infinite if no exchange)
!>                               - rcodcl(3) value flux density
!>                                 (negative if gain) in w/m2 or roughness
!>                                 in m if icodcl=6
!>                                 -# for the velocity \f$ (\mu+\mu_T)
!>                                    \gradv \vect{u} \cdot \vect{n}  \f$
!>                                 -# for the pressure \f$ \Delta t
!>                                    \grad P \cdot \vect{n}  \f$
!>                                 -# for a scalar \f$ C_p \left( K +
!>                                     \dfrac{K_T}{\sigma_T} \right)
!>                                     \grad T \cdot \vect{n} \f$
!> \param[in,out] disale        nodes displacement
!> \param[in]     xyzno0        vertex coordinates of initial mesh
!_______________________________________________________________________________

subroutine usalcl &
 ( itrale ,                                                       &
   nvar   , nscal  ,                                              &
   icodcl , itypfb , ialtyb , impale ,                            &
   dt     ,                                                       &
   rcodcl , xyzno0 , disale )

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

!===============================================================================
! Module files
!===============================================================================

use paramx
use numvar
use optcal
use cstphy
use cstnum
use entsor
use parall
use period
use ihmpre
use mesh

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

implicit none
!< [arg]
! Arguments

integer          itrale
integer          nvar   , nscal

integer          icodcl(nfabor,nvarcl)
integer          itypfb(nfabor), ialtyb(nfabor)
integer          impale(nnod)

double precision dt(ncelet)
double precision rcodcl(nfabor,nvarcl,3)
double precision disale(3,nnod), xyzno0(3,nnod)
!< [arg]
!< [loc_var]
! Local variables

integer          ifac, iel, ii
integer          inod
integer          ilelt, nlelt

double precision delta, deltaa
double precision D
double precision WAVEHT
double precision GRAVITY
double precision TWAVE
double precision AK
double precision AB
double precision DDX
double precision ARG
double precision ETA
double precision UIN
double precision DWDZ


integer, allocatable, dimension(:) :: lstelt
!< [loc_var]
!===============================================================================


!===============================================================================
! 1.  Initialization
!===============================================================================
!< [allocate_ale]
! Allocate a temporary array for boundary faces selection
allocate(lstelt(nfabor))
!< [allocate_ale]
!===============================================================================
! 2.  Assign boundary conditions to boundary faces here

!     One may use selection criteria to filter boundary case subsets
!       Loop on faces from a subset
!         Set the boundary condition for each face
!===============================================================================


D = 10.D0
WAVEHT = 2.D0
GRAVITY = 9.81D0
TWAVE = 10.0D0
AK = SQRT(0.75*WAVEHT/D**3)
AB = SQRT(GRAVITY*(D+WAVEHT))
DDX = AB*TWAVE

! Example: For boundary faces of color 4 assign a fixed velocity
!< [example_1]
if (.false.) then

  call getfbr('5', nlelt, lstelt)
  !==========

  do ilelt = 1, nlelt

    ifac = lstelt(ilelt)
    itypfb(ifac) = ientre
    
    ARG = AK*((cdgfbo(1,ifac)+DDX)-AB*TTCABS)
    ARG = min(max(ARG,-100.0D0),100.0D0)
    ETA = WAVEHT/cosh(ARG)**2
    UIN = AB*ETA/(D+ETA)
    DWDZ = 2.0D0*AK*D*UIN*tanh(ARG)/(D+ETA) 

    icodcl(ifac,iu)   = 1
    rcodcl(ifac,iu,1) = UIN 
    rcodcl(ifac,iu,2) = rinfin
    rcodcl(ifac,iu,3) = 0.D0

    icodcl(ifac,iv)   = 1
    rcodcl(ifac,iv,1) = DWDZ * cdgfbo(3,ifac)
    rcodcl(ifac,iv,2) = rinfin
    rcodcl(ifac,iv,3) = 0.D0

    icodcl(ifac,iw)   = 1
    rcodcl(ifac,iw,1) = 0.0D0
    rcodcl(ifac,iw,2) = rinfin
    rcodcl(ifac,iw,3) = 0.D0
                  
    icodcl(ifac,ipr)   = 3
    rcodcl(ifac,ipr,1) = 0
    rcodcl(ifac,ipr,2) = rinfin
    rcodcl(ifac,ipr,3) = 0.D0

  enddo

endif

!----
! End
!----
!< [deallocate_ale]
! Deallocate the temporary array
deallocate(lstelt)

!< [deallocate_ale]
return
end subroutine usalcl