Talk:Volumetric flow rate

Wiki Education Foundation-supported course assignment

This article was the subject of a Wiki Education Foundation-supported course assignment, between 25 February 2020 and 8 May 2020. Further details are available on the course page. Student editor(s): S.stickles.

Above undated message substituted from Template:Dashboard.wikiedu.org assignment by PrimeBOT (talk) 12:33, 17 January 2022 (UTC)

Angle between vectors

I think that perhaps a more careful choice of words should be made with regards to the statement of the special case when the velocity is perpendicular to the area. It is claimed that the angle between the two is 0 degrees, but if they were perpendicular the angle would be 90 degrees, in which case the entire expression would be zero. Perhaps it is better to say that the area vector is coincident with the velocity vector, and show this in terms of the scalar product? - 71.185.139.167 03:47, 6 November 2007

Apparently the wording problem has been resolved some time between 2007 and now. Nicknicknickandnick (talk) 23:22, 24 December 2010 (UTC)

Other uses

The lead seems to restrict the concept to a moving "volume of fluid". A freight train may move x cubic yards of gravel per day, which is also a volumetric flow rate.

I removed the sentence: "Volumetric flow rate is also linked to viscosity." The velocity profile is affected by viscosity, but the relationship between viscosity and volumetric flow rate seems less direct. The desired volumetric flow rate through a pipe may be achieved with a steeper velocity profile if the centerline velocity is high enough. -Ac44ck (talk) 17:04, 15 October 2008 (UTC)

Disambiguating "module"

The article on the Ardre (river) has this wikilink to module:

The mean of the annual flow rates or module, at Fismes over this period was shown to be 1,56 m³ per second.

From Google searching, I can find some uses of "module" in a hydrometry context measured in cubic centimeters per second (ccs). But I can't find a definition. I think it's a synonym for volumetric flow rate. Can anyone substantiate this claim?

I think it should be added to this article and to the disambiguation page. --Pnm (talk) 01:08, 4 June 2010 (UTC)

It's the physical meaning that matters. If you have fluid flow in volume units per time unit, then yes, it's volumetric flow rate, regardless of whether it's called a module, a schmodule, or any other niche name. Freederick (talk) 09:01, 23 May 2023 (UTC)

What would cause an angular flow?

The article speaks of the case when the velocity is at "an angle θ away from the perpendicular direction to A". I am having trouble imagining why, for example, water would ever leave a hole immediately at an angle away from perpendicular to the hole area. I would appreciate some detail and maybe a diagram of how that could ever be. Or does the article mean that we could for example, consider a tube, and if we wanted to, consider a cross sectional area at an angle off the perpendicular so that instead of considering an inuitively chosen circle, we instead consider an elliptical area? In that case, it is easier for my mind to think of the area as the deviator from typical rather than the velocity (as implied by the article's choice of wording) even though they are equivalent in terms of the task of angle measure between them. Nicknicknickandnick (talk) 23:41, 24 December 2010 (UTC)

Consider, to give but one example, the flow around an airfoil. The flow leaves the trailing edge at an angle, and no, the angle cannot be ignored. Freederick (talk) 08:53, 23 May 2023 (UTC)

Problems

This article is poorly written.

• Why is velocity an unrecognizable C and not the standard u or v?
• no structure to the article, this is just a loose collection of bitty-pieces.
• This equation $Q=AC\,\!$ is not the continuity equation at all. It is just the definition of Q. There is a huge differance between definitions and physical laws.
• what the hell is the divergance theorem used for? it is simply applied to the definition of Q - then a dead end. The formula doesn;t lead anywhere, it only re-states how Q can be calculated. readers will probably not even care...

I'm re-writing it - I can't look at it any longer. -- F = q(E + v × B) 17:43, 17 December 2011 (UTC)

btw this would be the continuity equation intended by that editor who wrote it:

$A_{1}C_{1}=A_{2}C_{2}\,\!$

or preferably:

$A_{1}v_{1}=A_{2}v_{2}\,\!$

but this is far too elementary - density should be included. For incompressible flows, just write $\rho _{1}=\rho _{2}\,\!$ (with explaination).-- F = q(E + v × B) 17:46, 17 December 2011 (UTC)

question

what's the source for eh Q=Av equation??? Godofwarfan333 (talk) 06:17, 18 November 2022 (UTC)

Compressible flow? Surely there's no such thing.

The entire article is based on the assumption that we are dealing with an incompressible liquid, and avoids the elephant in the room---gas flow---as if it conveniently didn't exist, or was somehow a marginal topic: "When the mass flow rate is known, and the density can be assumed constant. . ."

Well, the density cannot be assumed constant. What then?

And what if the gas is a mixture of different densities? Do you average based on volume fraction? Or based on mass fraction? How do you convert?

Yes, I can find this information in textbooks. But this is an established encyclopedia, FFS, not a grade school essay. The information should be here, it's the first place most would look. Freederick (talk) 08:36, 23 May 2023 (UTC)