Deriving Half-Max Velocity in Pipe Flow

AI Thread Summary
In pipe flow, the average velocity is established as half of the maximum velocity under specific conditions. This relationship can be derived by solving the Navier-Stokes equations in cylindrical coordinates, assuming incompressible flow, linear pressure decrease, finite flow rate, unidirectional flow, and zero velocity at the pipe walls. These assumptions simplify the analysis and lead to the conclusion that the average velocity is indeed half of the maximum velocity. Understanding this derivation is crucial for fluid dynamics applications. The principles outlined are fundamental for engineers and scientists working with pipe flow systems.
jonnygeordie
Messages
2
Reaction score
0
Could someone help me with this. In pipe flow show that the average velocity is half of the maximum velocity. I have it written in my notes that this is true, but not how to derive it.
 
Physics news on Phys.org
You can get the answer if you solve Navier-Stokes equation in cylindrical coordinates with the following assumptions:

1) Flow is incompressible.
2) Pipe pressure decreases linearly.
3) Flow rate is finite.
4) Flow rate is static, hence, the fluid only flows in one particular direction (you can guess which one based on the symmetry of a cylindrical pipe).
5) Flow rate at the sides of the pipe = 0.
 
Back
Top