CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > Software User Forums > ANSYS > CFX

What is density-weighted continuity equation

Register Blogs Community New Posts Updated Threads Search

Like Tree2Likes
  • 2 Post By ghorrocks

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   August 8, 2023, 17:01
Talking What is density-weighted continuity equation
  #1
New Member
 
Join Date: Aug 2023
Posts: 10
Rep Power: 3
NatpJ is on a distinguished road
Hi everyone,

I found this term as I was reading a paper, so I was just wondering what it meant by density-weighted continuity equation? I'm not so sure if it applies for multiphase flow of two fluids in CFX. Does CFX implement this in their equation? If not, how do I do that? Or if someone could explain what the text below means that would be helpful as well. Thank you so much.

The part of the text from the paper I was reading: " we solve for six momentum equations, together with mass conservation and an equation for the phase fraction which involves the difference of the density-weighted continuity equations (leading to a constraint for continuity that ensures conservation of mass even in the early, not fully converged, stages of the computation)".
NatpJ is offline   Reply With Quote

Old   August 9, 2023, 01:21
Default
  #2
Senior Member
 
Daniel
Join Date: Feb 2017
Location: Germany
Posts: 169
Rep Power: 9
zacko is on a distinguished road
Have a look in a book about the Favre averaging method of the conservation equations.
zacko is offline   Reply With Quote

Old   August 9, 2023, 06:39
Default
  #3
Super Moderator
 
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 17,854
Rep Power: 144
ghorrocks is just really niceghorrocks is just really niceghorrocks is just really niceghorrocks is just really nice
I think the question is about the density weighed multiphase equations, not Favre averaging equations (which are used on equations like the momentum equation as an averaging approach to get Reynolds stresses, commonly in turbulence models).

The density weighted multiphase equations are explained in the CFX documentation, eqn 5-23 for continuity.
Opaque and zacko like this.
__________________
Note: I do not answer CFD questions by PM. CFD questions should be posted on the forum.
ghorrocks is offline   Reply With Quote

Old   August 9, 2023, 07:56
Default
  #4
New Member
 
Join Date: Aug 2023
Posts: 10
Rep Power: 3
NatpJ is on a distinguished road
Quote:
Originally Posted by ghorrocks View Post
I think the question is about the density weighed multiphase equations, not Favre averaging equations (which are used on equations like the momentum equation as an averaging approach to get Reynolds stresses, commonly in turbulence models).

The density weighted multiphase equations are explained in the CFX documentation, eqn 5-23 for continuity.
I will have a look at the documentations. Thank you very much!!
NatpJ is offline   Reply With Quote

Reply

Tags
cfx, continuity equation, multiphase flow


Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
courant number increases to rather large values 6863523 OpenFOAM Running, Solving & CFD 22 July 6, 2023 00:48
Continuity Equation for multicomponent simulation lordluan CFX 15 May 19, 2020 19:36
p_rgh initial residual no change with different settings manuc OpenFOAM Running, Solving & CFD 3 June 26, 2018 16:53
Calculation of the Governing Equations Mihail CFX 7 September 7, 2014 07:27
AMI interDyMFoam for mixer nu problem danny123 OpenFOAM Programming & Development 8 September 6, 2013 03:34


All times are GMT -4. The time now is 17:19.