Chemical Engineering - Fluid Mechanics

Exercise :: Fluid Mechanics - Section 7
31.
If Blausius or Darcey friction factor is 'f _{1} ' then the Fanning friction factor is equal to

Answer: Option A

Explanation:

32.
Pick out the wrong statement pertaining to fluid flow.

A.
The ratio of average velocity to the maximum velocity for turbulent flow of Newtonion fluid in circular pipes is 0.5. B.
The Newtonion fluid velocity in a circular pipe flow is maximum at the centre of the pipe. C.
Navier-Stokes equation is applicable to the analysis of viscous flows. D.
Hagen-Poiseuille equation is applicable to the laminar flow of Newtonion fluids.

Answer: Option A

Explanation:

33.
A Newtonion liquid (ρ = density, μ = viscosity) is flowing with velocity v in a tube of diameter 'D '. Let Δp be the pressure drop across the length 'L '. For a laminar flow, Δp is proportional to

A.
L ρv2 /D B.
L μ;V /D2 C.
D ρv^{2} /L D.
μ V /L

Answer: Option A

Explanation:

34.
While starting a centrifugal pump, its delivery valve should be kept

A.
opened. B.
closed. C.
either opened or closed ; it does not make any difference. D.
either opened or closed; depending on the fluid viscosity.

Answer: Option B

Explanation:

35.
For flow past a flat plate, if x is the distance along the plate in the direction of flow, the boundary layer thickness is proportional to

Answer: Option A

Explanation: