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

Flow around the microscale tube in CFX4.4

Register Blogs Community New Posts Updated Threads Search

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   December 10, 2003, 05:13
Default Flow around the microscale tube in CFX4.4
  #1
hsinluen
Guest
 
Posts: n/a
Dear Sir,

I conduct the flow simulation around the micro-scale tube with diameter 100 micro meter. In this scale, belongs to the continum flow range. In build/analysis, I set the geometry scale factor 1.0e-6, the pressure field could not be predicted correctly. In the same condition, I don't set the geometry scale factors, the pressure distribution around the tube is predicted correctly.

My question is whether CFX 4.4 could simulate the flow in micro scale which is in the continum range.

If Yes, please tell me any tricks in simulating the micro-scale flow around the tube.

Thank you for your kindest help.
  Reply With Quote

Old   December 10, 2003, 17:22
Default Re: Flow around the microscale tube in CFX4.4
  #2
Glenn Horrocks
Guest
 
Posts: n/a
Hi hsinluen,

By "continuum range" I assume you mean laminar flow, and probably stokes flow where the inertial effects are negligible.

CFX4.4 can handle this type of flow. In fact you should find convergence very fast as there should be no seperations. Make sure you turn turbulence off by setting the turbulence model to laminar.

I don't know why you are having the difference with the scale factors in Build. Can you explain a bit more please?

Glenn
  Reply With Quote

Old   December 10, 2003, 21:53
Default Re: Flow around the microscale tube in CFX4.4
  #3
Jeff
Guest
 
Posts: n/a
Try,

1. Laminar flow (as suggested). 2. Make sure Pref is atmospheric and all pressure boundaries are relative (i.e. zero). At that scale you'll likely have very little pressure drop from cell to cell. You don't want to swamp out the precision with a large boundary pressure. 3. Run it in double precision, just in case the roundoff is killing the continuity equation.

Jeff
  Reply With Quote

Reply


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
Laminate flow through a tube with unexpected turbulence tommie OpenFOAM Running, Solving & CFD 1 September 15, 2008 11:15
Can 'shock waves' occur in viscous fluid flows? diaw Main CFD Forum 104 February 16, 2006 06:44
Question about Oscillating Flow in a Tube Ryan FLUENT 0 December 11, 2005 01:41
HElP!!!! Swirl flow in tube khairy FLUENT 0 August 4, 2005 19:04
A modeling problem of flow in a tube Jason CFX 0 July 21, 2004 16:29


All times are GMT -4. The time now is 00:29.