Difference between compressible and incompressible flow


by mahaesh
Tags: compressible, difference, flow, incompressible
mahaesh
mahaesh is offline
#1
Sep29-08, 04:32 AM
P: 12
Hi all
I am really confused with what is the actual meaning of compressible and incompressible flow?
Phys.Org News Partner Science news on Phys.org
Lemurs match scent of a friend to sound of her voice
Repeated self-healing now possible in composite materials
'Heartbleed' fix may slow Web performance
FredGarvin
FredGarvin is offline
#2
Sep29-08, 06:31 AM
Sci Advisor
FredGarvin's Avatar
P: 5,095
In a nutshell: Does density of the media change significantly?
tiny-tim
tiny-tim is offline
#3
Sep29-08, 06:43 AM
Sci Advisor
HW Helper
Thanks
tiny-tim's Avatar
P: 26,167
Hi mahaesh!

Incompressible flow is flow whose density is constant along any streamline.

For details see http://en.wikipedia.org/wiki/Compressible_flow

mahaesh
mahaesh is offline
#4
Sep29-08, 07:28 AM
P: 12

Difference between compressible and incompressible flow


Hi tiny-tim
Thanks for your reply but i am confusing because combustion is a compressible flow due to variation in density but in Computational Fluid dynamics analysis combustion treated as incompressible flow Why?
FredGarvin
FredGarvin is offline
#5
Sep29-08, 05:49 PM
Sci Advisor
FredGarvin's Avatar
P: 5,095
I am not familiar with what exactly you are doing, but in a constant flow process, like in a jet engine, there is actually a very small pressure drop across the burner (in a well designed burner). I wonder if that doesn't have something to do with what you are looking at.
Topher925
Topher925 is offline
#6
Sep29-08, 06:47 PM
Topher925's Avatar
P: 1,672
Quote Quote by mahaesh View Post
Hi tiny-tim
Thanks for your reply but i am confusing because combustion is a compressible flow due to variation in density but in Computational Fluid dynamics analysis combustion treated as incompressible flow Why?
I don't know why, since it obviously isn't an incompressible substance and I would assume any CFD model that assumed incompressible flow would be very inaccurate. The only exception would be if you are considering something like flame dispersion in the combustion chamber over a small period of time and are assuming the piston to have such small travel in that period that the change in volume can be neglected.


Register to reply

Related Discussions
Difference between incompressible viscous and incompressible inviscid flow. General Physics 1
incompressible fluid flow. Mechanical Engineering 7
compressible air flow thorugh pipe Mechanical Engineering 1
When can one assume Incompressible Flow? Mechanical Engineering 5