Talk:Non-Newtonian fluid

message: Where do constant-viscosity elastic (Boger) Fluids fit into this classification scheme? —Preceding unsigned comment added by 61.88.61.66 (talk) 02:44, October 7, 2005
:That would be a visco-elastic fluid.  From this article http://www.theage.com.au/news/national/300000-boger-fluid-prize-not-on-the-nose/2005/10/04/1128191716871.html  it soulds like the Boger fluid is a pretty rare thing--most of the traditional visco-elastic fluids, like shear thickening Silly Putty, also exhibit non-Newtonian viscosity changes.  In fact, I think most of the visco-elastic substances would be shear thickening, as shear thinning would seem to be incompatable with elasticity....    scot 14:13, 7 October 2005 (UTC)
replies: text: I'm not sure if this resolves anything, but Boger fluids exhibit constant viscosity; however their shear properties don't satisfy the equation required for classification as Newtonian, so they're a unique class of non-Newtonian fluid. Jelliott4 (talk) 13:25, 16 March 2011 (UTC)
thread_title:  Boger Fluids 

message: Blood is listed as both a pseudo-plastic and generalized newtonian fluid.  Is this accurate? —Preceding unsigned comment added by Tuckerekcut (talk • contribs) 23:37, February 4, 2006
:Many fluids exhibit more than one non-Newtonian behavior; for example, Silly Putty is both shear thickening and visco-elastic.  It's entirely possible that blood exhibits a number of non-Newtonian behaviors, and that pseudo-plastic just happens to be the dominant trait.  See the above discussion for my earlier suggestions on reorganizing the chart to make these overlaps less confusing.  scot 23:50, 4 February 2006 (UTC)
replies: text: Ah, taking out the "non" in front of "newtonian" certainly makes a difference.  It is the case that some fliuds exhibit Newtownian behavior under some circumstances and not under other circumstances.  My guess is that bood does exhibit non-Newtownian behavior at times, as it is a suspension of particles (cells) in a fluid (plasma) and such suspensions often behave oddly--corn starch in water, for example, which exhibits pretty radical shear thickening, or iron particles in oil, which thickens in the presence of a magnetic field (making it a magnetorheological fluid).  My guess is that that the issue is at what point you split a fulid into "Newtownian" or "Non-Newtownian" categories.  Probably all fluids behave in a non-Newtownian manner under the right circumstances (particularly at very small scales), and it's all a matter of picking the threshold.  scot 16:47, 9 February 2006 (UTC)
thread_title:  Double Listing 

message: I propose Complex fluids be merged with this page. Complex fluid is already redirected here. I'm not an expert on fluid mechanics, so I don't know if this makes sense. I'll help merge if it does. -FrankTobia (talk) 03:42, 17 November 2007 (UTC)
replies: text: The article on complex fluids seems mostly interested in multiphasic flow. Which is completely different from being non-newtonian. So I think the merger should not happen. CyrilleDunant (talk) 08:51, 17 November 2007 (UTC)
replies: text: CyrilleDunant is correct - the merger should not happen.  Those that suggested it no nothing about basic Physics.  —Preceding unsigned comment added by 86.143.220.162 (talk) 23:15, 21 November 2007 (UTC)
thread_title:  Merger proposal 

message: I know that eggs don't behave like a newtonian fluid... for an easy example, make a scrambled egg.  As you stir the egg faster, it slops around less.  Don't know how this would get classified or anything though.  —Preceding unsigned comment added by 137.112.141.205 (talk) 19:20, 5 December 2007 (UTC)
thread_title:  eggs 

message: Is urine a Non-Newtonian fluid? Also, would it be appropriate to request a scheme whereby all fluids are classified as either Newtonian or Non-Newtonian? __meco (talk) 10:01, 15 August 2009 (UTC)
replies: text: Urine is (as far as I know, usually, at normal temperature and pressure conditions, baring certain medical conditions) adequately simulated using a Newtonian approximation. As for the classification scheme, no. It  might depend on temperature, scale considered, speed, etc. Fluids themselves are not Newtonian or not: it is only a way of saying that for the state/conditions considered a linear approximation of the behaviour is satisfactory or not.CyrilleDunant (talk) 12:17, 15 August 2009 (UTC)

text: Appreciated. __meco (talk) 12:25, 15 August 2009 (UTC)
thread_title:  Urine 

message: What does the photo of the corn starch on the speaker demonstrate? It doesn’t seem to be referenced anywhere in the article (unless I missed it), and I can’t imagine what it is meant to be showing - does it go solid when you turn the speaker on, or liquify, or levitate, or what?79.67.148.152 (talk) 11:02, 25 November 2009 (UTC)
replies: text: Nobody has put in an explanation since you asked, and it's useless without one.71.203.125.108 (talk) 15:38, 16 May 2010 (UTC)
replies: text: Here is a link to a video that shows what I can only assume the photo is trying to depict.  http://www.youtube.com/watch?v=F2i-IPiuCwk&NR=1  98.173.153.226 (talk) 20:05, 10 September 2010 (UTC)
thread_title:  What is the photo illustrating? 

message: The opening paragraph does not really describe a Non-Newtonian fluid. Ideally an opening paragraph should explain what it is, not that it is simply 'not something'. The Newtonian Fluid description could be modified to fit the opening paragraph. I'd do it myself, but unlike some wikipedia bureaucrats who throw their weight around trying to simplify or standardize fields they know nothing about, I'd prefer if someone else with expertise handle this because articles of this nature should be handled by experts rather than just someone with a plan to make this comply to some esoteric standard. Klichka (talk) 21:36, 6 April 2011 (UTC)
thread_title:  The opening paragraph is too confusing 

message: Custard is listed in the table as a Newtonian fluid. This is contradicted by comment under section on "Bingham plastic" which says that "...Newtonian fluids have flat featureless surfaces when still", which is not true of custard. It is also contradicted by comment on custard page stating that custard is thixotropic. See http://en.wikipedia.org/wiki/Custard.
Does "custard" have divergent enough meanings that both categorizations could be true in different situations? Tom10001 (talk)  —Preceding undated comment added 19:31, 28 January 2013 (UTC)
thread_title: Custard listed as a Newtonian Fluid

message: In the first table of non-newtonian page,  viscoelasticity has been set separate from  time dependent non-newtonian fluids.
but  "Viscoelastic materials have elements of both of these properties and, as such, exhibit time-dependent strain." from
Viscoelasticity.  — Preceding unsigned comment added by Aditya8795 (talk • contribs) 12:51, 1 September 2014 (UTC)
thread_title:  Isnt Viscoelastic fluids time dependent? 

message: The Cary Sneider quote I object to is also from 2013 and certainly not the first use of goop in a classroom.  Reverted User:Fuborc edit.--Lucas559 (talk) 21:04, 17 June 2015 (UTC)
thread_title:  Questionable fact/date 

message: The table "Comparison of non-Newtonian, Newtonian, and viscoelastic properties" would be more useful with headings. Columns 1, 3 and 4 could be "Type", "Properties" & "Examples" but I'm not sure about column 2. Tigerboy1966  07:44, 1 January 2017 (UTC)
thread_title:  Table heading 

message: The article states that cornstarch 'dissolved in water' displays shear thickening. This is wrong since the phenomenon referred to concerns cornstarch dispersed at high concentration in cold water. This doesn't dissolve the starch to any significant extent and the thickening observed is due to the cubic starch particles bunching up and not flowing past each other when any more than a small force is applied. It's analogous to the picture with wet sand. A true cornstarch solution (made by dissolving/cooking in very hot water) is actually more like a gel, and non-Newtonian in the more common pseudoplastic sense.  — Preceding unsigned comment added by 81.102.219.142 (talk) 18:06, 15 August 2017 (UTC)
thread_title:  Cornstarch 

message: In a non-Newtonian fluid, the relation between the shear stress and the shear rate is different. The fluid can even exhibit time-dependent viscosity. Therefore, a constant coefficient of viscosity cannot be defined.
I just dividing a sentence to eliminate an awkwardness.  This made the original text more problematic in meaning: the original text seemed to want to imply that the first sentence (and not what I have now placed in the second sentence) on its own is sufficient to justify the third sentence, but the line of implication is locally opaque to me (and I didn't first read and comprehend the entire article). — MaxEnt 11:25, 10 September 2017 (UTC)
replies: text: Okay—I get it now, the emphasis is on constant.  I had missed the sentence about linearity. — MaxEnt 11:28, 10 September 2017 (UTC)
thread_title:  Non-definition of viscosity 

message: The article currently has it both ways. 2.24.119.66 (talk) 00:49, 6 May 2018 (UTC)
replies: text: I'm not 100% sure, but it doesn't seem to be a proper name, so I have standardised this with lower case O. Bazonka (talk) 17:42, 17 March 2019 (UTC)
thread_title:  Oobleck: O or o? 

message: This article implies the existence of Newtonian Fluids. There are none. That is, over the entire range of stress/shear rate, no fluid is Newtonian. The article on Newtonian Fluids says:"While no real fluid fits the definition perfectly, many common liquids and gases, such as water and air, can be assumed to be Newtonian for practical calculations under ordinary conditions." But I know of no fluid that does not have a linear relationship between shear rate and stress IF observed over a sufficiently small range. (Of course, a limiting (infinitesimal) value is required for the existence of the quantity (assuming a continuum).) It would be good to mention that a Newtonian Fluid is a simple ideal case which many fluids approximate in common situations, but no fluids* follow Newton's Law of Constant Viscosity perfectly over the entire range of shear rate. Non-Newtonian Fluids exhibit a non-linear (non-constant) shear/stress curve under common 'normal' (i.e. non extreme) situations. *I don't know if superfluids (e.g. He-3 or He-4 at cryogenic temperatures), have zero viscosity over the entire shear rate range, but I'd guess not.(of course, that assumes we can create indefinitely large or small shears, and we clearly can't.)207.155.85.22 (talk) 23:48, 20 February 2022 (UTC)
thread_title:  Newtonian Fluid