CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > General Forums > Main CFD Forum

parasitic flow in twophase flow simulation

Register Blogs Members List Search Today's Posts Mark Forums Read

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   April 4, 2007, 10:31
Default parasitic flow in twophase flow simulation
  #1
dusky.He
Guest
 
Posts: n/a
It is reported there are significant parasitic flow besides the interface in the simulation of two-phase flow using CSF or CSS model

Is there any good way to reduce it?

Thanks a lot

  Reply With Quote

Old   April 5, 2007, 14:07
Default Re: parasitic flow in twophase flow simulation
  #2
CFDtoy
Guest
 
Posts: n/a
Parasitic flows near the interface are created due to the errors accumulated in the interface curvature estimation. There are several ways to reduce it. recently, an energy method to reduce the spurious current was reported in JCP by Kothe (I guess). Doesnt really matter CSF/CSS just a few differences exist in the methodology. Both require curvature estimation and thats where the problem begins !

CFDtoy
  Reply With Quote

Old   April 5, 2007, 18:39
Default Re: parasitic flow in twophase flow simulation
  #3
Hrvoje Jasak
Guest
 
Posts: n/a
Well, yes, but the balance is very important. If you are doing capillary flows and the parasitic velicyt is 100 m/s, you can throw your result away. Therefore, writing a decent surface capturing algorithms is still critical.

Hrv
  Reply With Quote

Old   April 9, 2007, 14:09
Default Re: parasitic flow in twophase flow simulation
  #4
CFDtoy
Guest
 
Posts: n/a
The magnitude of parasitic velocity Up ~ ratio of the viscosity to surface tension(the capillary number). One way to check the balance is to compute, dP = sigma*curvature variation in the neighborhood. Since the VOf methods use a single flow field, any variation inthe volume frac gradient reflects in the local force effects.

Smoothing, say using a laplacian in a unstrc mesh could reduce the spurious force effects (note CSF etc require smoothened VOF scalar in the field).

Still, the need for good curvature evaluation is critical !

CFDtoy

  Reply With Quote

Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

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
Channel flow setup in Large-eddy simulation Weihua Main CFD Forum 6 November 17, 2015 10:33
Is there any software for hypersonic flow simulation? atmcfd Main CFD Forum 3 November 29, 2010 00:28
Multiphase flow - simulation crashing yschati CFX 14 November 16, 2010 18:29
Expert parameter to stop the fluid flow simulation KK CFX 1 February 25, 2008 17:29
flow simulation across a small fan jane luo Main CFD Forum 15 April 12, 2004 18:49


All times are GMT -4. The time now is 23:16.