[Nek5000-users] Further to the issue of ffx, ffy and ffz

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

Hi,

The documentation says:
P054: fixed flow rate dir: |p54|=1,2,3=x,y,z
P055: vol.flow rate (p54>0) or Ubar (p54<0)

So for instance if you want to run a pipe with bulk flow of unity, you set:
p54: -3 (z)
p55: 1

How this is done in the latest versions I do not know, as we do not use 
those for pipe production runs.

Philipp

On 2018-02-25 16:06, nek5000-users at lists.mcs.anl.gov wrote:
> Hi,
> 
> May I push the following question further? Is there anyone know what are 
> the exact meaning for para(54) and (55) in rea file? Such as, what's the 
> difference between: 0,0 and -3 1 for (54) and (55) respectively? what's 
> meaning for sign (+) or (-)?
> 
> Kind regards,
> 
> Zhai
> 
> 
> Hi Philipp,
> 
> Yes, they are shear velocity and bulk velocity. Can I say if the ffx, ffy
> or ffz equal to (u_t/u_b)^2, the flow is specified as a fixed pressure
> gradient in the channel, and parameter(54) and para(55) in rea file are
> fixed as 0. Otherwise, if the all ffx, ffy and ffz are 0, the flow is fixed
> at flow rate rather than pressure gradient?
> 
> Cheers,
> 
> Zhai
> 
> 
> 
> 
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