Fully Developed Flow: Laminar vs Turbulent

Click For Summary
The discussion centers on the definition of fully developed flow in laminar versus turbulent conditions. Participants agree that fully developed flow implies a constant velocity profile along the stream coordinate, but there are nuances regarding temperature and concentration gradients. One contributor suggests that for flow to be considered fully developed, all fluid parameters except for the pressure gradient must remain constant. Another points out that variations in temperature can affect viscosity, complicating the definition of fully developed flow. The conversation highlights the complexity of fully developed flow and the need for a comprehensive understanding of fluid dynamics.
Kensiber
Messages
2
Reaction score
0
Does the definition of fully developed flow is different for laminar and turbulent?
I understand the fact that the entrance length are different in laminar and turbulent flows, but I believe the definition of fully hydrodynamically developed flow means that the velocity profile (hence momentum) doesn’t change with respect to the stream coordinate.
Please give some insights?
Thanks

[moderator moved the text from summary to body.]
 
Last edited by a moderator:
Engineering news on Phys.org
That sounds correct to me. Why did you think something else was possible?
 
I thought this definition of "fully developed flow" may change with the temperature gradient and concentration gradient between the fluid and pipe wall. Otherwise, it should be defined as follows.
"Except the pressure gradient in the pipe section (which balances shear resistance to sustain uniform velocity profile) all fluid parameters such as temperature and concentration difference must be zero to have a fully developed flow." I couldn't find something similar to this definition in any textbooks. [there are explanations about concentration and thermal boundary layers separately, but couldn't see one description including all these phenomena]
 
Well, if the temperature is varying radially, it must also be changing axially, so the flow can't be fully developed unless the viscosity is independent of temperature. At least, that is my take on this.
 
  • Like
Likes Kensiber
Had my central air system checked when it sortta wasn't working. I guess I hadn't replaced the filter. Guy suggested I might want to get a UV filter accessory. He said it would "kill bugs and particulates". I know UV can kill the former, not sure how he thinks it's gonna murder the latter. Now I'm finding out there's more than one type of UV filter: one for the air flow and one for the coil. He was suggesting we might get one for the air flow, but now we'll have to change the bulb...

Similar threads

Replies
2
Views
2K
  • · Replies 1 ·
Replies
1
Views
4K
  • · Replies 7 ·
Replies
7
Views
9K
  • · Replies 10 ·
Replies
10
Views
2K
  • · Replies 5 ·
Replies
5
Views
7K
  • · Replies 2 ·
Replies
2
Views
2K
Replies
1
Views
2K
  • · Replies 11 ·
Replies
11
Views
3K
Replies
10
Views
23K