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

Manning's equation calculates mean flow velocity in open channels using Manning's roughness coefficient n, hydraulic radius R, and channel slope S.

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

Hydraulic radius R = A/P, where A is the cross-sectional area of flow and P is the wetted perimeter; it quantifies flow efficiency relative to boundary friction.

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

A centrifugal pump's rotating impeller accelerates fluid radially outward, converting mechanical (shaft) energy to kinetic energy, which the volute casing then converts to pressure.

Question 4

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

Accepted Answer

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

Answer

The head-capacity curve plots TDH vs. Q, showing that as flow rate increases, the head a centrifugal pump can deliver typically decreases.

Question 5

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

Accepted Answer

Subcritical or supercritical

Answer

The Froude number Fr = V/√(gD); Fr < 1 is subcritical (tranquil) flow, Fr = 1 is critical, and Fr > 1 is supercritical (rapid) flow.

(ETC) Engineering Technician Certification Practice Test

(ETC) Engineering Technician Certification Practice Test

ETC ETC Hydraulics & Fluid Mechanics 3