# Geometry.f90 - Calculation of geometric properties

```
!Sample program for solving Lid-driven cavity flow test using SIMPLE-algorithm
! Calculation of Xc and Yc with possibility for further development modul
!Copyright (C) 2010  Michail Kiričkov
!Copyright (C) 2016  Michail Kiričkov, Kaunas University for Technology

!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.

!**********************************************************************
!**********************************************************************
Subroutine Geom
include 'icomm_1.f90'
! calculation Xc,Yc
! ------------------------------------------------------------------------
do  2 I=2,NXmax
do  2 J=2,NYmax
Xc(I,J)=(  X(i-1,j-1) + X(i-1,j  ) + &
X(i  ,j  ) + X(i  ,j-1)      ) * 0.25
Yc(I,J)=(  Y(i-1,j-1) + Y(i-1,j  ) + &
Y(i  ,j  ) + Y(i  ,j-1)     ) * 0.25
2 continue
! ------------------------------------------------------------------------
do 4 I=2,NXmax
Xc(i,1      ) = ( X(i  ,1    ) + X(i-1,1    ) ) * 0.5
Xc(i,NYmax+1) = ( X(i  ,NYmax) + X(i-1,NYmax) ) * 0.5
Yc(i,1      ) = ( Y(i  ,1    ) + Y(i-1,1    ) ) * 0.5
Yc(i,NYmax+1) = ( Y(i  ,NYmax) + Y(i-1,NYmax) ) * 0.5
4 continue
! ------------------------------------------------------------------------
Xc(1      ,      1) = X(    1,    1)
Xc(NXmax+1,      1) = X(NXmax,    1)
Xc(      1,NYmax+1) = X(    1,NYmax)
Xc(NXmax+1,NYmax+1) = X(NXmax,NYmax)
Yc(1      ,      1) = Y(    1,    1)
Yc(NXmax+1,      1) = Y(NXmax,    1)
Yc(      1,NYmax+1) = Y(    1,NYmax)
Yc(NXmax+1,NYmax+1) = Y(NXmax,NYmax)
!--------------------------------------------------------------------------
do 5 J=2,NYmax
Yc(1      ,j ) = ( Y(1     ,j) + Y(1    ,j-1) ) * 0.5
Yc(NXmax+1,j ) = ( Y(NXmax ,j) + Y(NXmax,j-1) ) * 0.5
Xc(1      ,j ) = ( X(1     ,j) + X(1    ,j-1) ) * 0.5
Xc(NXmax+1,j ) = ( X(NXmax ,j) + X(NXmax,j-1) ) * 0.5
5 continue
! ------------------------------------------------------------------------
! Xi (vertical)
Do 101 I=1,NXmax
Do 101 J=1,NYmax-1
X_xi(I,J) = X(i  ,j+1) - X(i  ,j  )
Y_xi(I,J) = Y(i  ,j+1) - Y(i  ,j  )
101 continue

! Eta (horisontal)
Do 102 I=1,NXmax-1
Do 102 J=1,NYmax
X_et(I,J) = X(i+1,j  ) - X(i  ,j  )
Y_et(I,J) = Y(i+1,j  ) - Y(i  ,j  )
102 continue
!--------------------------------------------------------------------------
! Xi (vertical)
Do 201 I=1,NXmaxC
Do 201 J=1,NYmax
Del_X_xi(i  ,j  ) =  Xc(i  ,j+1) - Xc(i  ,j  )
Del_Y_xi(i  ,j  ) =  Yc(i  ,j+1) - Yc(i  ,j  )
201 continue
! Eta (horisontal)
Do 202 I=1,NXmax
Do 202 J=1,NYmaxC
Del_X_et(i  ,j  ) =  Xc(i+1,j  ) - Xc(i  ,j  )
Del_Y_et(i  ,j  ) =  Yc(i+1,j  ) - Yc(i  ,j  )
202 continue
!--------------------------------------------------------------------------
Do 303 I=2,NXmaxC-1
Do 303 J=2,NYmaxC-1
Dx_c(i,j) = X(i,j) - X(i-1,j)
Dy_c(i,j) = Y(i,j) - Y(i,j-1)
303 continue
Return
End

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