[Nek5000-users] stokes flow with time-dependent boundary

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

Hi Lailai,

I have used the approach you proposed for solving multiple
steady stokes problems... you use an artificially large
timestep.  That works.

If you really have a time-dependent boundary condition, there
is no reason you can't just use the unsteady Stokes solver
with whatever timestep is required to accurately resolve your
temporal bcs.   Note that, in this case, you would indeed have
the inertial term rho du/dt present in the physics.

Paul


On Mon, 19 Dec 2011, nek5000-users at lists.mcs.anl.gov wrote:

> Hello, guys,
>
> i am a new guy to Nek5000, i saw the manual of nek5000 that it can solve the 
> steady stokes flow.
> i guess when i solve such a flow, do i need to set it as a transient 
> simulation with time-derivative term included to get  a steady-state 
> solution? or, i can solve it by a direct solver method to get the solution 
> immediately?
>
> since i want to add some time-dependent boundary condition for the steady 
> stokes flow, so it will be pretty nice if i can solve it using the direct 
> solver, for each time step, i solve one stokes flow; if nek5000 cannot solve 
> it in such a way, i guess i have to use the first way; then for each time 
> step i have to solve a transient problem to approach the steady state with 
> some artificial time step used.
>
> i am not sure if i have stated my problem clearly. hopefully you guys have 
> some experience on the feasibility of the two ways mentioned above. Thank you 
> in advance.
>
> lailai
>
>
>
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