Go Back   Physics Help Forum > High School and Pre-University Physics Help > Thermodynamics and Fluid Mechanics

Thermodynamics and Fluid Mechanics Thermodynamics and Fluid Mechanics Physics Help Forum

Like Tree2Likes
  • 1 Post By Woody
  • 1 Post By mscfd
LinkBack Thread Tools Display Modes
Old Dec 27th 2018, 11:40 AM   #1
Junior Member
Join Date: Dec 2018
Posts: 1
Compressible vs. Incompressible flow

Hello dears,

I have seen many explanations in various references about the definition of compressible flow.
In fact, changing the density of the flow as a result of pressure variations leads to a compressible flow.
Now, my question is that what if the density of the fluid flow changes as a result of temperature changes which come from heat transfer on boundaries.
Imagine a situation in which the fluid flow density is changing by temperature but the Mach number is low. Is it a compressible or incompressible flow?

Best Regards
sasanghomi is offline   Reply With Quote
Old Dec 28th 2018, 12:44 PM   #2
Senior Member
Woody's Avatar
Join Date: Jun 2016
Location: England
Posts: 691
Incompressible flow is always an approximation,
However it is far easier to model incompressible flow than compressible.

The question becomes, are the flow conditions close enough to incompressible for the simpler model to be used as an acceptable approximation.

If the fluid has a thermocline, or similar boundary, you may be able to assume incompressible conditions on either side of the boundary,
but you would have to make special provision in any model for the boundary.
topsquark likes this.
Woody is offline   Reply With Quote
Old Dec 29th 2018, 09:28 AM   #3
Junior Member
mscfd's Avatar
Join Date: Sep 2014
Location: Brasília, DF - Brazil
Posts: 26
Some points...

Incompressible fluid is a material property

Incompressible flow describes a flow property

Pont 1 - In an incompressible flow, the density of a fluid element doesn't change along its pathline. So you can have an incompressible flow of compressible fluid in the case of low Mach numbers or in stratified flows.

Point 2 - An incompressible fluid always results in an incompressible flow
topsquark likes this.
Work on:

General thermal systems


Micro-drop fluid mechanics
mscfd is offline   Reply With Quote

  Physics Help Forum > High School and Pre-University Physics Help > Thermodynamics and Fluid Mechanics

compressible, flow, incompressible

Thread Tools
Display Modes

Similar Physics Forum Discussions
Thread Thread Starter Forum Replies Last Post
Calculating equal flow through parallel flow pipes? clone477 Thermodynamics and Fluid Mechanics 7 Mar 28th 2018 08:33 PM
The entropy change of solids and incompressible liquids studiot Thermodynamics and Fluid Mechanics 1 Feb 9th 2018 09:07 AM
Reynolds number in incompressible flow Rocco30 Thermodynamics and Fluid Mechanics 0 Mar 16th 2016 04:58 PM
Compressible Fluid Air arpitv7 Thermodynamics and Fluid Mechanics 6 Aug 10th 2015 04:03 PM
The incompressible continuity equation Devlan Advanced Mechanics 2 Jun 2nd 2014 02:20 PM

Facebook Twitter Google+ RSS Feed