subroutine bound_duvdt

! Periodic boundary exchange 

use crmx_vars
implicit none
         
integer i,j,k

	  do k=1,nzm
	   do j=1,ny
	     dudt(nxp1,j,k,na) = dudt(1,j,k,na)
	   end do
	  end do

	  if(RUN3D) then

	    do k=1,nzm
	     do i=1,nx
	      dvdt(i,nyp1,k,na) = dvdt(i,1,k,na)
	     end do
	    end do

	  endif
	
end subroutine bound_duvdt