[Nek5000-users] Change boundary condition type with time?

[nek5000-users at lists.mcs.anl.gov]

Hi Johan,

Here is a piece of code adapted from one of my simulations that you could
try to include in you userchk.

      include 'TSTEP' ! time, ifield
      include 'INPUT' ! cbc

      integer iel, ifc
      integer icalld
      save icalld
      data icalld /0/

      if (icalld .eq. 0 .and. ifield .eq. 1 .and. time .gt. T) then
         icalld = 1
         nface = 2*ndim


         do iel=1,nelv


            do ifc=1,nface
               if ("face belongs to part B") then   ! Identify boundary B
here
                  cbc (ifc,iel,ifield) = 'O  ' ! or 'o  ' or 'on ' or 'ON '
depending on what is needed
               endif


            enddo


         enddo

         ! Reset BC flags and masks
         call setlog
         call bcmask
      endif

Best,
Nicolas

P.S.: please ignore previous message, that was a wrong manipulation.

On Wed, Apr 11, 2018 at 2:08 PM, <nek5000-users at lists.mcs.anl.gov> wrote:

> Hi Neks,
>
>
> I wonder if it is possible to have boundary conditions that chage type
> with time?
>
>
> I want to simulate a flow where I make a 'puff' of fluid through a hole in
> a wall.
>
> After the puff is made it continues to evolve without beeing forced.
>
>
> Mathematically, this is what I want:
>
>    1. Dirichlet boundary conditions (ux,uy,uz) = (0,0,1) for the velocity
>    at a part B of the boundary up to a time T.
>    2. Open boundary condition for the velocity at B for time > T.
>
>
> Is this possible to implement?
>
>
> Best,
>
>
> Johan
>
>
>
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>
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