# Talk:Compressible flow

## Old message

I believe the first line in the article is incorrect. My aerodynamics text covers compressible flows in the regime under Mach 1. I suspect but do not know that supersonic flow is incompressible with shock waves resulting off the aircraft. Can you verify or explain why the lead line is accurate as is. Thanks mirwin

Mirwin removed that message two minutes after posting it. Today, no relevant comments on talk pages should be erased, so I've restored the comment. Graham87 07:11, 15 December 2009 (UTC)

## Editing

I'm planning on majorly revamping this page as there's so much to discuss on this topic and nothing here. I'm knowledgeable on compressible fluid mechanics, but only slightly as it applies to aerodynamics. Any help on this side of things would be appreciated. Iron_Engineer (talk) 03:28, 2 July 2009 (UTC)

I've done a major revamp of the page. I've added a bit, especially on internal flows. I've also taken the liberty to remove the cleanup and no references templates. If anyone feels it still needs cleaning up, feel free to add the template back in. Thanks Alphanumeric Sheep Pig (talk) 07:12, 20 January 2011 (UTC)

I've also left in the original referencing style (where all the references are cited at the end) but added in text citations as well. It bugs me that two different styles are used. I prefer them all to be in text, especially since there are more than just one or two of them. Alphanumeric Sheep Pig (talk) 07:19, 20 January 2011 (UTC)

The first sentence states that compressibility is defined as a variation in density, and the second sentence states that the threshold is that the Mach number "must be greater than 0.3". No justification is provided, and the Mach number section gives nothing of value to justify that number. Dimensional analysis does say that a Mach number >0.3 would yield a significant enough variation of density, but it is not proven in the article that the Mach number is necessary and sufficient. Low Mach number heated flows can have large density variations. Shouldn't the article specify that the Mach threshold is only valid for isentropic flows? 150.135.210.182 (talk) 19:55, 3 February 2016 (UTC)

## Review

This page really needs a review and revamping —Preceding unsigned comment added by Iyer.arvind.sundaram (talkcontribs) 04:15, 11 June 2010 (UTC)

I would like to first discuss here on the list of things to be put up on this page. I request comments on the same, and suggestions for the structure of the article. Iyer.arvind.sundaram (talk) 04:22, 11 June 2010 (UTC)

Thank you for volunteering to do some work on this article. I think the structure of the article, as shown by the list of contents, is appropriate. However, the text throughout the article could do with some refinement to improve the scientific language and remove unnecessary jargon. Dolphin (t) 05:47, 11 June 2010 (UTC)

## Conservation of mass

${\displaystyle {{\partial \rho } \over {\partial t}}=-\operatorname {div} (\rho \cdot {\vec {v}})}$
Generally written in the form below?
${\displaystyle {{\partial \rho } \over {\partial t}}+\nabla \cdot (\rho \,{\vec {v}})=0}$ —Preceding unsigned comment added by Salih (talkcontribs) 08:15, 3 October 2010

If this is a question to which you want an answer, this Talk page is inappropriate and unlikely to produce an answer. Questions of a mathematical nature are regularly asked and answered at the Mathematics Reference Desk. Questions of a scientific nature are regularly asked and answered at the Science Reference Desk. Dolphin (t) 11:30, 3 October 2010 (UTC)

Sorry, it was not intended to be a question. I just wanted to show the editor who wrote the continuity equation above the common form of continuity equation. 12:48, 3 October 2010 (UTC)

## Update needed?

I think this article may need updating to cover liquids as well as gases. See Theory of sonics. Biscuittin (talk) 19:00, 24 July 2014 (UTC)