Mechanical Engineering - Hydraulics and Fluid Mechanics - Discussion

Discussion Forum : Hydraulics and Fluid Mechanics - Section 2 (Q.No. 2)
2.
The velocity corresponding to Reynold number of 2800, is called
sub-sonic velocity
super-sonic velocity
lower critical velocity
higher critical velocity
Answer: Option
Explanation:
No answer description is available. Let's discuss.
Discussion:
27 comments Page 2 of 3.

Denish said:   10 years ago
It is right if Re>2000 then it is called critical but this is true only when flow through pipe. But for different flow conditions Re. Value are different. In this question they have not mention any type of conditions then how we can decide the right answer.

Harry said:   9 years ago
Low critical velocity is laminar flow.
High critical velocity is turbulent flow.

Here they give 2800 is laminar flow so, it should be a low critical velocity.

Srikantha A said:   8 years ago
The flow at which laminar flow stops is called lower critical velocity (RN 2000).

The flow at which turbulent flow starts is called higher critical velocity (RN 2800).

Tagese said:   8 years ago
@Girish Changavi, It should be

If Re <2000, tts laminar flow.
If Re > 4000 its turbulent flow.
If between 2000 to 4000 its transition flow.

Here Re is 2800, so it's not higher critical velocity.

Naveenkumar T said:   8 years ago
If Re <2000, tts laminar flow.
If Re > 4000 its turbulent flow.
If between 2000 to 4000 its transition flow.

The velocity at which flow changes from laminar to transition is called LOWER CRITICAL.
VELOCITY and that at which transition changes to turbulent is called UPPER CRITICAL VELOCITY.

Nirav said:   8 years ago
Yes, you are totally right @Naveenkumar T.

Aakash said:   8 years ago
Raynold number = 2800 shows that flow is changing from the transition to turbulent and for this kind of flow, velocity is termed as upper critical velocity.

When flow changes from laminar to transition velocity is termed as lower critical velocity.

Aakash said:   8 years ago
Raynold number = 2800 shows that flow is changing from the transition to turbulent and for this kind of flow, velocity is termed as upper critical velocity.

When flow changes from laminar to transition velocity is termed as lower critical velocity.

Kavya said:   8 years ago
What if Reynolds number =2000?

Aniruddh said:   7 years ago
It's not given whether the flow is in a pipe or flat plate?


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