c-----------------------------------------------------------------------
c
c     8/27/03
c
c     This is the .usr file for a 3D Hagen-Poiseiulle flow, assuming
c     a unit-radius pipe (in the x-y plane) with flow in the z direction.
c
c     Periodic boundary conditions in z are assumed.
c
c     A unit-amplitude parabolic profile is specified as U = 1-r^2.
c
c     The required forcing function, dp/dz, is given by:
c
c     A*dx*dp/dz = -2 mu * 2piR*dx      ( R = 1 )
c
c
c          dp
c     ==>  -- = - 4 mu
c          dz
c
c-----------------------------------------------------------------------
      subroutine uservp (ix,iy,iz,ieg)
      include 'SIZE'
      include 'TOTAL'
      include 'NEKUSE'
C
      udiff =0.
      utrans=0.
      return
      end
c-----------------------------------------------------------------------
      subroutine userf  (ix,iy,iz,ieg)
      include 'SIZE'
      include 'TOTAL'
      include 'NEKUSE'

      ffx = 0.0
      ffz = 0.0
      ffy = 0.0

!     include swirl
      if (y .gt. 0) ffy=temp*temp/y

      return
      end
c-----------------------------------------------------------------------
      subroutine userq  (ix,iy,iz,ieg)
      include 'SIZE'
      include 'TOTAL'
      include 'NEKUSE'
C
      qvol   = 0.0

!     include swirl     
      if (y .gt. 0) then
             visc = param(2)
             qvol = -uy*temp/y
      endif

      return      
      end
c-----------------------------------------------------------------------
      subroutine userchk    ! called once per step
      include 'SIZE'
      include 'TOTAL'
c      call avg_all

      
      
      
      return
      end
c-----------------------------------------------------------------------
      subroutine userbc (ix,iy,iz,iside,ieg)
      include 'SIZE'
      include 'TOTAL'
      include 'NEKUSE'
    
      REAL::PI,sw
      PI=3.14159
      sw=0.8944


      ux=1.0
      uy=0.0
      uz=0.0
      temp=0.0

      if (x .eq. 0.0) then
      if (y .lt. 1.0) then                      
      temp=y*(2-y**2)*sw
      else
      temp=sw/y
      end if      
      end if

      return
      end
c-----------------------------------------------------------------------
      subroutine useric (ix,iy,iz,ieg)
      include 'SIZE'
      include 'TOTAL'
      include 'NEKUSE'


      ux = 0.
      uy = 0.
      uz = 0.
      temp=0.0

      return
      end
c-----------------------------------------------------------------------
      subroutine usrdat
      include 'SIZE'
      include 'TOTAL'

      return
      end
c-----------------------------------------------------------------------
      subroutine usrdat2
      include 'SIZE'
      include 'TOTAL'


      return
      end
c-----------------------------------------------------------------------
      subroutine usrdat3
      return
      end
c-----------------------------------------------------------------------
c
c automatically added by makenek
      subroutine usrsetvert(glo_num,nel,nx,ny,nz) ! to modify glo_num
      integer*8 glo_num(1)
      return
      end