Why should an ideal fluid be incompressible?

  • #1
44
1
Hi,

I read that an ideal fluid needs to be frictionless and incompressible.
Please explain why, especially the incompressible part?

Thanks
 

Answers and Replies

  • #2
boneh3ad
Science Advisor
Insights Author
Gold Member
3,271
945
It makes their mathematical treatment substantially easier.
 
  • #3
Lok
555
23
Hi,

I read that an ideal fluid needs to be frictionless and incompressible.
Please explain why, especially the incompressible part?


Thanks
The bulk modulus of most materials is very high compared to usual pressures, resulting in insignificant compression of most materials. Solids usually are even more incompressible than liquids. Wiki the bulk modulus to get a feel for the forces involved.
 
  • #4
cjl
Science Advisor
1,891
461
As boneh3ad said, "ideal", in the context of a lot of math and science isn't saying that we wish real fluids behaved like that, it's about making assumptions/simplifications that make analysis easier (or in some cases, that make analysis possible at all). Compressibility dramatically increases the difficulty of fluid dynamics, so if you can ignore it, it makes a lot of sense to do so.
 
  • #5
boneh3ad
Science Advisor
Insights Author
Gold Member
3,271
945
As my PhD advisor often said, an ideal fluid is an 18-year-old, single malt Scotch whisky.
 
  • Like
Likes DanielSauza, cjl and jim mcnamara
  • #6
cjl
Science Advisor
1,891
461
I think that's a definition I can get behind.
 
  • Like
Likes boneh3ad

Related Threads on Why should an ideal fluid be incompressible?

Replies
5
Views
10K
  • Last Post
Replies
13
Views
3K
Replies
4
Views
15K
Replies
1
Views
1K
  • Last Post
Replies
4
Views
3K
  • Last Post
Replies
7
Views
6K
Replies
2
Views
1K
  • Last Post
Replies
1
Views
8K
Top