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

Defining a variable Viscosity ??

Register Blogs Community New Posts Updated Threads Search

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   June 17, 2008, 05:41
Default Defining a variable Viscosity ??
  #1
MAB
Guest
 
Posts: n/a
Any idea of how to define viscosity of water to be a funcions of x coordinate? I want to increase the viscosity after a specified distance in horizontal direction. Any suggestion 'll be appreciated. Thanking in advance. MAB
  Reply With Quote

Old   June 18, 2008, 19:08
Default Re: Defining a variable Viscosity ??
  #2
Rogerio Fernandes Brito
Guest
 
Posts: n/a
do you want to know how to make the expression or what expression to use?

For example: dynamic viscosity as a function of x coordinate times 2.

ownvisc(X)

A = 1.0 [Pa s] B = 1.0 [m]

ownvisc=(A*(2*(X/B)))

Make a CEL expression and edit this material on what you are working in!

  Reply With Quote

Old   June 19, 2008, 07:32
Default Re: Defining a variable Viscosity ??
  #3
MAB
Guest
 
Posts: n/a
Thanks Rogerio F.B. i will try this. what i exactly want is to increase the viscosity of water by 10 times after say x=20m where as total length along x-axis is 30m. i have tried it usin step function as step((x-20)/1m)*10*viscwater + actual viscosity of water but the solver didn't run ..each time it gave an error. any suggestion
  Reply With Quote

Old   June 19, 2008, 11:06
Default Re: Defining a variable Viscosity ??
  #4
CycLone
Guest
 
Posts: n/a
The solver will not allow the viscosity to change based on spatial coordinates make sense physically.

What are you physically trying to model? Why is the water viscosity changing at all?

-CycLone
  Reply With Quote

Old   June 20, 2008, 06:45
Default Re: Defining a variable Viscosity ??
  #5
MAB
Guest
 
Posts: n/a
Hi CycLone, I am modelling water waves on free surface. neer outlet i want to increase the viscosity of water so that the waves gets damped before approching the outlet, i want to do this to avoid refelection. (it has been easily done in starccm+) any further suggestion?(
  Reply With Quote

Old   July 10, 2008, 09:14
Default Re: Defining a variable Viscosity ??
  #6
Jesse
Guest
 
Posts: n/a
step((x/1[m]-20)*10*viscwater+actual visosity of water
  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
emag beta feature: charge density charlotte CFX 4 March 22, 2011 10:14
error in COMSOL:'ERROR:6164 Duplicate Variable' bhushas COMSOL 1 May 30, 2008 05:35
Vortex methods with variable viscosity? labarba Main CFD Forum 15 February 4, 2005 05:57
Replace periodic by inlet-outlet pair lego CFX 3 November 5, 2002 21:09
variable viscosity -NOT! George Bergantz Main CFD Forum 15 September 19, 2000 15:28


All times are GMT -4. The time now is 10:25.