About the Moody Diagram –

 

1. In the laminar zone – f decreases as Nr increases! 

2. f = 64/Nr. 

3. transition zone – uncertainty – not possible to    predict - 

4. Beyond 4000, for a given Nr, as the relative

    roughness term D/ε increases (less rough),

    friction factor decreases 

5. For given relative roughness, friction  

    factor decreases with increasing Reynolds

    number till the zone of complete turbulence 

6. Within the zone of complete turbulence –  

    Reynolds number has no affect. 

7. As relative roughness increases (less rough) –

    the boundary of the zone of complete

    turbulence shifts (increases)

• If you know the – relative roughness, Reynolds number – 

   you can compute the friction factor from the    Moody Diagram