StokesSecond

! ***********************************
! coutte flow by simple Euler method 
! 2016.10.22
! ***********************************

      include 'param.h'

      call init

      do n=1,nt

      time=n*dt

!     boundary condition
      u(1 )=0.0; un(1)=0.0
      u(ny)=amp*sin(2.*pi*time/wp); un(ny)=u(ny)

      do j=2,ny-1

      rh=cc*(u(j+1)+u(j-1)-2.*u(j)) + alfa*dt
      un(j)=rh+u(j)   ! next time

      enddo ! j

      u=un  ! for next time

      if(mod(n,np).eq.0) write(10,'(2000f8.3)') (u(j),j=1,ny)

      enddo ! time

      close(10)

      stop
      end

! *******************************
! initial condition for array
! *******************************
      subroutine init
      include 'param.h'

      u =0. ! zero clear
      un=0. ! zero clear

      open(10,file='flow.dat')

      return
      end