# Chemical Engineering - Fluid Mechanics - Discussion

Discussion Forum : Fluid Mechanics - Section 1 (Q.No. 2)
2.
Laminar flow of a Newtonion fluid ceases to exist, when the Reynolds number exceeds
4000
2100
1500
3000
Explanation:
No answer description is available. Let's discuss.
Discussion:
14 comments Page 1 of 2.

For laminar flow, Re should be equal to or less than 2100.

Laminar flow is less than or equal to 2100.

The above question doesn't mention about the system.
we have two type of value for laminar.

1. for circular pipe----- Re<= 2100
2. for flat plate ------- Re<= 5*10^5

For flow in a conduit:
Re<2100 Laminar Flow, Sheer Stress depends on viscosity but not on density.
2100<Re<4000 : Transient Flow
Re>4000 Turbulent flow depends on density.

This is true only in case of flow through pipes. we cannot generalize this for every case. Re num is different for every case.

For Laminar flow, Reynold's number is less than or equal to 1(Re <= 1).

Dhruvin virani said:   1 decade ago
Laminar flow is less than or equal to 2100. And Re>4000 Turbulent flow.

JayaMsuba said:   10 years ago
For open channel flow,

If Re <500 or 600. laminar
> 2000 or 2100. turbulent.

For circular pipe flow,

If Re <2000. laminar.
> 4000. turbulent.
Here, Re=rho*v*d/mu...d=dia of pipe.

Here both formulae are important to keep in mind. because sometime this may confuse you.

Khawal said:   10 years ago
Laminar flow is in linear motion and having re less than 2100, after increase the re the turbulence is so that velocity increase.

Rajisha said:   9 years ago
Re below 2100 is laminar flow in case of circular pipes.