ME or MEng Master of Engineering Fluid Mechanics and Hydraulics 3

Question 1

A pump's specific speed is used to:

Accepted Answer

Classify pump type and predict performance

Answer

Determine pipe wall thickness

Answer

Calculate NPSH requirements only

Answer

Measure impeller blade stress

Question 2

Cavitation in pumps occurs when local fluid pressure drops below:

Accepted Answer

The vapor pressure of the fluid

Answer

Atmospheric pressure

Answer

The pump discharge pressure

Answer

The fluid's critical pressure

Question 3

The boundary layer on a flat plate transitions from laminar to turbulent at approximately which local Reynolds number?

Accepted Answer

Re_x = 5 × 10⁵

Answer

Re_x = 500

Answer

Re_x = 2,300

Answer

Re_x = 10⁷

Question 4

Manning's equation in open-channel hydraulics relates flow velocity to:

Accepted Answer

Hydraulic radius, channel slope, and roughness coefficient

Answer

Pipe diameter and fluid density

Answer

Froude number and Darcy friction factor

Answer

Reynolds number and wetted perimeter only

Question 5

Stokes' Law for drag on a small sphere at very low Reynolds number gives drag force as:

Accepted Answer

F_D = 3πμVD

Answer

F_D = ½ρV²A·C_D

Answer

F_D = ρgV_submerged

Answer

F_D = μ(dV/dy)A

Question 6

The energy grade line (EGL) in pipe flow lies above the hydraulic grade line (HGL) by a distance equal to:

Accepted Answer

V²/2g (velocity head)

Answer

z (elevation head)

Answer

p/γ (pressure head)

Answer

hf (friction head loss)