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

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

Dear Zhai,


p54 = -3   ( implies fixed flow rate in z, with Wbar=p55 )

p55 = 1    ( implies Wbar = 1 )


would be appropriate for a fixed flow rate in the z-direction.


If you have ffx nonzero, then one of two things can happen.

If you also have periodicity in x, then you will have flow in the x direction.   Otherwise, you will simply have a pressure gradient in x.


If, on the other hand, you have ffz nonzero, then the flow will be unchanged, but the apparent z pressure drop will be different.


Paul


PS - Normally, I would run with


p54 = -1

p55 =  1


ffx = 0


which would be fixed axial flow rate (assuming "x" is the axial direction), with Ubar = 1.


Then,


"grep volf logfile"  would reveal the pressure drop as a function of time.



________________________________
From: Nek5000-users <nek5000-users-bounces at lists.mcs.anl.gov> on behalf of nek5000-users at lists.mcs.anl.gov <nek5000-users at lists.mcs.anl.gov>
Sent: Friday, March 23, 2018 1:25:00 PM
To: nek5000-users at lists.mcs.anl.gov
Subject: [Nek5000-users] Further to ffx, ffy and ffz

Hi Paul,

Thanks for your reply regarding on the questions of  ''Further to the issue of ffx, ffy and ffz''. May I ask you if I keep p54=-3, p55=1, will the fluid be changed if ffx not eqauls to 0 (supposed x is streamwise direction)  in the same time?

And dear Philipp,

May I know what you ususally set for the pipe flow if p54 and p55 are not used, fixing flow rate or fixing pressure gradient? and how you do you set if the flow considering the interaction between fluid and particles for the two-phase flow?

Kind regards,

Zhai
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