[Nek5000-users] Infinite Prandtlnumber with Nek5000

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

hello, Jan,

great that you have tested them. I always want to try, but am too lasy...
Could you say a little bit about the aphysical
oscillations? Do you see oscillations for one iteration, or they appear 
because of the
time stepping approach I suggested? Sometimes I indeed see this in the 
velocity field
  for a low-quality mesh with low GLL numbers, normally the spatial 
velocity oscillations
are gone by either using a mesh with better quality (same GLL) or 
increasing the number GLL points for
the same mesh.

I think the way suggested by Paul will significantly speedup the 
simulation compared to the way
I suggested, although trivial inertia is introduced.  have you observed 
the speedup?

thanks,

lailai

On 2015/8/14 9:00, nek5000-users at lists.mcs.anl.gov wrote:
> Hi Paul,
> thanks for the advice. I tested some simple 2D cases and the method 
> seems to work quite good. The idea in the other posts had a tendency 
> to produce unphysical oscillations. We might look into testing Nek 
> against other mantle convection codes, where varying viscosity and 
> parallelisation is still a problem.
>
> Thanks again,
> Jan
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-- 
Lailai Zhu
Laboratory of Fluid Mechanics and Instabilities LFMI
EPFL STI IGM LFMI ME A2 408 (Bâtiment ME) Station 9
CH-1015 Lausanne Switzerland