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

wall law modifications non-newtonian fluids

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

Reply
 
LinkBack Thread Tools Display Modes
Old   January 10, 2013, 10:14
Default wall law modifications non-newtonian fluids
  #1
C.C
Member
 
CC
Join Date: Jun 2011
Posts: 52
Rep Power: 6
C.C is on a distinguished road
Hi all,

I have changed the standard wall function in the k-e turbulence model by UDF, but I need to confirm if it is correctly implemented and the unique way to do this is looking for the u+ profile. Someone can help me, how can I obtain u+ from Fluent? In UDF there is any pre-defined "variable" for wall shear stress or friction velocity?
I'm studying a non-Newtonian turbulent flow in a pipe. My main doubt is how Fluent treat the non-Newtonian properties (viscosity as a function of shear rate) with the turbulence. Please, if someone have any information (papers or another type of information) can help me.
Regards
C.C is offline   Reply With Quote

Old   February 23, 2014, 17:17
Default
  #2
New Member
 
Majid
Join Date: Jan 2014
Location: Canada
Posts: 23
Rep Power: 3
sharif88 is on a distinguished road
Hi
I am struggling to model turbulent flow of polymer solutions (dilute, power law fluids).
I have tried CFX and also FLUENT by modifying the viscosity term but I am keep getting wring results,
The most important thing for me is get the correct pressure drop and velocity profile which are coming completely wrong,
Looks like you are dealing with the same sort of simulation so I would appreciate if you help me out on this,
Thanks
sharif88 is offline   Reply With Quote

Old   February 25, 2014, 05:48
Default
  #3
C.C
Member
 
CC
Join Date: Jun 2011
Posts: 52
Rep Power: 6
C.C is on a distinguished road
Hi!

In my case, I modified the viscosity as a function of shear rate and also the wall functions in Fluent using an UDF... The velocity profile is more similar with the experimental result with this modifications. In the pulp case as in the polymer cases the pressure drop is lower than the water pressure drop in the same conditions. By modifying the viscosity and the wall function I get lower pressure drop but not yet similar to the experimental result.
Regards
C.C is offline   Reply With Quote

Reply

Thread Tools
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 On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Law of the wall in the presence of pressure gradient yidongxia Main CFD Forum 2 August 5, 2012 14:40
UDF for wall slipping HFLUENT Fluent UDF and Scheme Programming 0 April 27, 2011 12:03
Star CCM+ issue (VOF and Non newtonian power law) Sam CD-adapco 3 January 23, 2009 08:39
Multicomponent fluid Andrea CFX 2 October 11, 2004 05:12
wall in fluids flow. Andrew Garrard FLUENT 3 January 23, 2004 03:13


All times are GMT -4. The time now is 16:03.