gravity driven drainage of yield stress fluid

tsh850227 · February 18, 2014, 11:18

Hi all,

is there anybody have any experience on the gravity driven drainage of yield stress fluid around a vertical plate? i want to do the modelling of this case, but no theory could be found to do the validation. i want to deduce by myself, but i cannot image what the profile will be.

thanks in advance.

ghorrocks · February 18, 2014, 17:24

What is a yield stress fluid? Do you mean a fluid with a with a yield stress non-Newtonian viscosity?

This sounds very specialised. You will need to do a literature search to find this.

Alternately: http://www.lmgtfy.com/?q=yield+stres...vertical+plate

tsh850227 · February 18, 2014, 17:31

Quote:

Originally Posted by ghorrocks

What is a yield stress fluid? Do you mean a fluid with a with a yield stress non-Newtonian viscosity?

This sounds very specialised. You will need to do a literature search to find this.

Alternately: http://www.lmgtfy.com/?q=yield+stres...vertical+plate

yes, you are right. a non-newtonian fluid with yield stress, such as bingham plastic and herschel-bulkley fluid.

tsh850227 · February 21, 2014, 11:09

Quote:

Originally Posted by ghorrocks

What is a yield stress fluid? Do you mean a fluid with a with a yield stress non-Newtonian viscosity?

This sounds very specialised. You will need to do a literature search to find this.

Alternately: http://www.lmgtfy.com/?q=yield+stres...vertical+plate

hi,

i built a model with power-law fluid and finish the simulation. the result is good by comparing it to theory. but, when i selected a yield stress fluid, simulation will terminate by large corrant number error. so i turn to looking for theory about this problem, but one week searching online cannot give me any valueable result. so any guidance from you ?

ghorrocks · February 22, 2014, 04:31

You have to expect you will have a hard time getting convergence with a non-Newtonian fluid model. First of all check that your flow is physically possible (for instance correctly set, and you are not pushing more fluid through an oriface than choked flow allows). With non-Newtonian models you can introduce new and unusual limits to flow which do nto apply to normal fluids.

If that is OK then you have to improve the stability of the numerics. The answer to that (as always), is better mesh quality, double precision numerics, smaller time step and/or better initial condition.

February 18, 2014, 11:18	gravity driven drainage of yield stress fluid	#1
tsh850227 Member Join Date: Jan 2012 Posts: 30 Rep Power: 14	Hi all, is there anybody have any experience on the gravity driven drainage of yield stress fluid around a vertical plate? i want to do the modelling of this case, but no theory could be found to do the validation. i want to deduce by myself, but i cannot image what the profile will be. thanks in advance.

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
how to get scalar stress of the fluid in Fluent	iceraining01	Main CFD Forum	0	September 29, 2005 02:30
Intl Conf Computational Methods in Fluid Power	Jacek Stecki	Main CFD Forum	0	November 10, 2002 05:49
yield stress	Fellouah	FLUENT	2	October 1, 2002 10:50
My Revised "Time Vs Energy" Article For Review	Abhi	Main CFD Forum	2	July 9, 2002 09:08
Terrible Mistake In Fluid Dynamics History	Abhi	Main CFD Forum	12	July 8, 2002 09:11

February 18, 2014, 17:24		#2
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,703 Rep Power: 143	What is a yield stress fluid? Do you mean a fluid with a with a yield stress non-Newtonian viscosity? This sounds very specialised. You will need to do a literature search to find this. Alternately: http://www.lmgtfy.com/?q=yield+stres...vertical+plate

February 22, 2014, 04:31		#5
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,703 Rep Power: 143	You have to expect you will have a hard time getting convergence with a non-Newtonian fluid model. First of all check that your flow is physically possible (for instance correctly set, and you are not pushing more fluid through an oriface than choked flow allows). With non-Newtonian models you can introduce new and unusual limits to flow which do nto apply to normal fluids. If that is OK then you have to improve the stability of the numerics. The answer to that (as always), is better mesh quality, double precision numerics, smaller time step and/or better initial condition.