# Non-Newtonian Fluids Property

 User Name Remember Me Password
 Register Blogs Members List Search Today's Posts Mark Forums Read

 LinkBack Thread Tools Display Modes
 February 24, 2009, 20:20 Non-Newtonian Fluids Property #1 Ben Guest   Posts: n/a HI I have Non-Newtonian fluids property (viscosity as function of shear rate) but have no idea how to input it into Flow-3D material property. So can anyone advice on this?

 February 24, 2009, 21:33 Re: Non-Newtonian Fluids Property #2 HC Guest   Posts: n/a If the strain rate is within the upper range during the whole simulation, meaning the stain rate is very high, the carreau equation presented in FLOW3D manual may be simplified as power law if mu_inf happens to be zero. Basically, if you look at the carreau equation, mu_inf = 0; E_T = 1; #given the temperature is constant lambda_00 = 0; lambda_0 = 0; lambda_2 = 0; From there, you take "Ln" on both sides and it will turn into a linear equation, then you should be able to find the exponential coefficient (1-n)/2 and mu_0. If the strain rate in the simulation covers not just the upper range, you may send the data to support@flow3d.com and see what else could be done.

 February 25, 2009, 01:24 Re: Non-Newtonian Fluids Property #3 Ben Guest   Posts: n/a Hi HC for my case the shear rate is cover entire range, so it is not a linear graph. Noticed that Flow-3d didn't user define function to enable this. anyway will check with support team on this.

 February 27, 2009, 00:54 Re: Non-Newtonian Fluids Property #4 michael barkhudarov Guest   Posts: n/a Ben, FLOW-3D has a fairly general hence complex function for the viscosity vs. strain rate (it's in the Theory Manual). As HC was saying, you'd first need to pick up which terms in it to use, then define the coefficients for these terms. Some coefficients can be determined from the asymptotic behavior at zero and infinite strain rates, and the rest from the fitting. Obviously, the more terms you use the harder it will be to do the fitting. One can also introduce a user-function unto the provided FORTRAN function, but this will require programming and compiling. In this year's release the user will be able to define the non-Newtonian viscosity tabular input. Michael

 February 27, 2009, 01:58 Re: Non-Newtonian Fluids Property #5 Ben Guest   Posts: n/a Hi Michael It good know about the improvement made on non-Newtonian input, do u have any idea when the new release will be available?

 March 1, 2009, 02:42 Re: Non-Newtonian Fluids Property #6 michael barkhudarov Guest   Posts: n/a We are shooting for the end of summer.

April 21, 2009, 12:03
viscoplastic model
#7
Member

xianghong wu
Join Date: Mar 2009
Posts: 57
Rep Power: 9
Quote:
 Originally Posted by michael barkhudarov ;93241 We are shooting for the end of summer.
HI,
I am wondering if viscoplastic model could be input when you release the tabular input? Thank you.

Wendy

 April 26, 2009, 22:52 #8 Senior Member   michael barkhudarov Join Date: Mar 2009 Posts: 332 Rep Power: 10 I don't know. What does the viscosity depend on in this case?

April 28, 2009, 10:57
viscoplastic model depends on strain rate and temperature
#9
Member

xianghong wu
Join Date: Mar 2009
Posts: 57
Rep Power: 9
I will use the constitutive model according to Bas Jan Emile van Rens's thesis: finte element simulation of the aluminum extrusion process shape prediction for complex profiles. the constitutive model is as attatchment.
Thank you.

Wendy
Attached Files
 constitve equations.doc (45.5 KB, 28 views)

 Thread Tools Display Modes Linear Mode

 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 OffTrackbacks are On Pingbacks are On Refbacks are On Forum Rules

 Similar Threads Thread Thread Starter Forum Replies Last Post Irene Fyrippi FLUENT 11 September 28, 2015 14:28 ziemowitzima OpenFOAM Running, Solving & CFD 21 April 23, 2015 06:14 Kimo FLUENT 0 July 22, 2007 11:36 phil FLUENT 0 January 18, 2007 03:43 IĆ±igo Main CFD Forum 0 October 4, 2005 09:36

All times are GMT -4. The time now is 19:52.

 Contact Us - CFD Online - Top