ETC ETC Hydraulics & Fluid Mechanics 3

Question 1

Manning's equation (V = (1/n) × R^(2/3) × S^(1/2)) is used primarily to calculate:

Accepted Answer

Flow velocity in open channels and culverts

Answer

Friction losses in pressurized water mains

Answer

Pump head requirements for lifting water

Answer

Groundwater seepage through soil

Question 2

The hydraulic radius (R) of an open channel cross-section is defined as:

Accepted Answer

The ratio of flow area to wetted perimeter (A/P)

Answer

Half the maximum flow depth

Answer

The ratio of wetted perimeter to flow area

Answer

The square root of the flow area

Question 3

A centrifugal pump transfers energy to a fluid primarily through:

Accepted Answer

A rotating impeller that imparts kinetic energy converted to pressure

Answer

Reciprocating pistons that compress the fluid

Answer

A diaphragm that displaces fixed fluid volumes

Answer

Meshing gears that trap and pressurize fluid

Question 4

The pump performance (head-capacity) curve shows the relationship between:

Accepted Answer

Total dynamic head (TDH) and volumetric flow rate (Q)

Answer

Pump efficiency and motor power input

Answer

NPSH required and impeller diameter

Answer

Shaft speed and fluid temperature

Question 5

The Froude number in open channel flow is used to classify flow as:

Accepted Answer

Subcritical or supercritical

Answer

Laminar or turbulent

Answer

Steady or unsteady

Answer

Pressurized or non-pressurized

Question 6

Net Positive Suction Head Available (NPSHa) must always be:

Accepted Answer

Greater than the pump's required NPSH (NPSHr) to prevent cavitation

Answer

Equal to NPSHr for optimal efficiency

Answer

Less than NPSHr to maximize suction lift

Answer

Calculated only for positive-displacement pumps

Question 7

The Hazen-Williams formula is most commonly used in water distribution design to estimate:

Accepted Answer

Friction head loss in pressurized water pipes

Answer

Open channel flow velocity in storm sewers

Answer

Pump efficiency at reduced impeller speed

Answer

Groundwater recharge rates in aquifers