Talk:Drag (physics)

This is the talk page for discussing improvements to the Drag (physics) article. This is not a forum for general discussion of the subject of the article.

Put new text under old text. Click here to start a new topic. New to Wikipedia? Welcome! Learn to edit; get help. Assume good faith Be polite and avoid personal attacks Be welcoming to newcomers Seek dispute resolution if needed Article policies Neutral point of view No original research Verifiability

Find sources: Google (books · news · scholar · free images · WP refs) · FENS · JSTOR · TWL

Archives: 1

This  level-4 vital article is rated C-class on Wikipedia's content assessment scale. It is of interest to the following WikiProjects:

Physics: Fluid Dynamics High‑importance Physics portal This article is within the scope of WikiProject Physics, a collaborative effort to improve the coverage of Physics on Wikipedia. If you would like to participate, please visit the project page, where you can join the discussion and see a list of open tasks. High This article has been rated as High-importance on the project's importance scale. This article is supported by Fluid Dynamics Taskforce. Engineering High‑importance Engineering portal This article is within the scope of WikiProject Engineering, a collaborative effort to improve the coverage of engineering on Wikipedia. If you would like to participate, please visit the project page, where you can join the discussion and see a list of open tasks. High This article has been rated as High-importance on the project's importance scale. Aviation Aviation portal This article is within the scope of the Aviation WikiProject. If you would like to participate, please visit the project page, where you can join the project and see lists of open tasks and task forces. To use this banner, please see the full instructions. This article has been checked against the following criteria for B-class status: Referencing and citation: criterion not met Coverage and accuracy: criterion not met Structure: criterion met Grammar and style: criterion met Supporting materials: criterion met Spaceflight High‑importance Spaceflight portal This article is within the scope of WikiProject Spaceflight, a collaborative effort to improve the coverage of spaceflight on Wikipedia. If you would like to participate, please visit the project page, where you can join the discussion and see a list of open tasks. High This article has been rated as High-importance on the project's importance scale.

The content of Aerodynamic drag was merged into Drag (physics) on 3 January 2018. The former page's history now serves to provide attribution for that content in the latter page, and it must not be deleted as long as the latter page exists. For the discussion at that location, see its talk page.

Archives

1

Caption required

The image showing relative amounts of form drag and skin friction needs a caption. How do I add one? Thanks. Pieter1963 (talk) 22:10, 21 July 2021 (UTC)[reply]

I have made it this far. Perhaps you can fine-tune it further. Dolphin (t) 14:00, 23 July 2021 (UTC)[reply]

Shape and flow	Form Drag	Skin friction
	~0%	~100%
	~10%	~90%
	~90%	~10%
	~100%	~0%
Your caption goes	here	& here

I couldn't make it work so added separate text. Cheers. Pieter1963 (talk) 22:38, 24 July 2021 (UTC)[reply]

Base drag

The article stated "base drag, (aerodynamics) a pressure drag due to flow separation at the base of a projectile[15] or termination of an aircraft fuselage with a flat area, such as is noticeable on the BAE Systems Hawk.". However, according to Doug McLean in "Understanding Aerodynamics: Arguing from the Real Physics" pp 210-211, base drag is not distinct from form drag. "The problem with the term 'base drag,' however, is that it has no defensible definition. Here are three logically possible candidates I know of, along with the reasons why they don't work... So it seems that defining base drag in a rigorous quantitative way is hopeless. And without a workable definition, 'base drag' seems questionable, even just as a concept."

I have removed the offending sentence. cagliost (talk) 10:28, 25 May 2022 (UTC)[reply]

Stokes flow drag coefficient unit.

I calculate the unit to be kg/s; please confirm and add to the article. Michael Hodgson (talk) 05:26, 7 June 2022 (UTC)[reply]

Coefficients of all kinds are, in my experience, dimensionless. The drag coefficient is sometimes described as “dimensionless drag”. Can you explain how you have calculated the drag coefficient to be in units of kg/s? Dolphin (t) 10:33, 7 June 2022 (UTC)[reply]

Wiki Education assignment: Technical and Professional Writing

This article was the subject of a Wiki Education Foundation-supported course assignment, between 17 January 2024 and 7 May 2024. Further details are available on the course page. Student editor(s): Eelaraa (article contribs).

— Assignment last updated by Eaturvegeez (talk) 19:07, 10 February 2024 (UTC)[reply]

Calculus article inside this one

When i browse this article on my PC there is an entire article about calculus in the middle, starting at a "at high velocities" section 78.88.136.21 (talk) 17:36, 27 December 2024 (UTC)[reply]

Can confirm, no idea how to fix. 86.60.128.16 (talk) 17:51, 27 December 2024 (UTC)[reply]

Seems like purging the page fixed this somehow. I have no idea why this even happens. 86.60.128.16 (talk) 17:53, 27 December 2024 (UTC)[reply]

in the US, Frisbee is still a registered trade mark (not yet a generic noun)

so technically this article should speak of 'flying discs' instead 108.65.77.184 (talk) 17:15, 25 March 2025 (UTC)[reply]

Misleading statement that "Unlike other resistive forces, drag force depends on velocity."

This statement is factually incorrect!

The most common "other" resistive force, Newtonian friction does depend on velocity! F = cv

It depends linearly on velocity!

The important difference with drag is that drag very often has a relevant contribution that is *nonlinear* (quadratic) in velocity.

I would suggest rephrasing it as:

"Unlike other resistive forces which are frequently depend linearly on velocity, contributions that are nonlinear in velocity are often highly relevant for the drag force." Gsteele13 (talk) 14:03, 7 October 2025 (UTC)[reply]

I assume the intent of the words "unlike other resistive forces" is that in dry friction, the friction force is considered to be independent of the sliding velocity. At Friction#Laws of dry friction, Coulomb's Law of Friction is quoted as Kinetic friction is independent of the sliding velocity.

You have mentioned "Newtonian friction". Is that different to Coulomb friction? Dolphin (t) 12:46, 9 October 2025 (UTC)[reply]

From my side, I come from a field of research where we study dynamics of oscillators and indeed I do not usually think about static friction.

For example, the equations of motion of a damped harmonic oscillator considers a (viscous) damping force linearly proportional to velocity:city:

Harmonic oscillator

Viscous damping

Damping

About dynamic Coulomb forces, if a friction force is truly independent of velocity, then you can end up in a situation where the dynamics is not stable: at zero velocity, there must be no force, otherwise the object would spontaneously start moving on its own…

I just looked up Coulomb friction (it’s been a while…):

Coulomb damping

In particular, you can see that although the magnitude of coefficient of the model of Coulomb damping is independent of velocity, if you write it more rigorously in an equation of motion, you must include the term with “sign” of the velocity: the dynamic Coulomb friction force is actually dependent on velocity in the sense that it is proportional to the sign of the velocity (important to produce a numerically well behaved equation of motion). It’s there, it is just “hidden” in typical formulations.

(Also interesting to note: the cusp-like nature of the sign function will cause strange nonlinear dissipative behaviour at very low amplitudes…)

BTW, this I found a pretty interesting plot:

https://commons.wikimedia.org/wiki/File:Static_kinetic_friction_vs_time.png

From Static friction part of the Friction#Static friction article.

I must say I am, as a physicist, a bit surprised about the emperical Coulomb law of friction, I would be curious how often this model is applicable in reality, as as a physicist, we nearly always model (dynamic) friction as linearly proportional to velocity.

I have learned a lot, but I would still stand by the statement that it is not an unusual feature that friction forces are linear in relative velocity. To me, at least, the most interesting nature of the drag force is the transition to a nonlinear dissipation at higher velocities, hence my suggestion of a reformulation Gsteele13 (talk) 09:36, 13 October 2025 (UTC)[reply]