ASCE Hydraulics and Fluid Mechanics 2

Question 1

Manning's roughness coefficient (n) in open channel flow primarily accounts for:

Accepted Answer

Boundary resistance due to channel surface texture

Answer

Channel slope and cross-sectional shape

Answer

Fluid viscosity and density

Answer

Froude number effects on wave speed

Question 2

The hydraulic radius (R) used in Manning's equation is defined as:

Accepted Answer

The ratio of flow area to wetted perimeter

Answer

Half the width of the channel cross-section

Answer

The ratio of wetted perimeter to flow area

Answer

The depth at which the Froude number equals 1

Question 3

Water hammer in a pipeline is primarily caused by:

Accepted Answer

Rapid changes in flow velocity such as sudden valve closure

Answer

Excessive pipe slope causing supercritical flow

Answer

High Reynolds numbers causing turbulent eddies

Answer

Cavitation at the pump impeller

Question 4

Which of the following best describes specific energy in open channel flow?

Accepted Answer

Energy per unit weight measured with respect to the channel bottom as datum

Answer

Total energy measured above a datum at the channel bed

Answer

The sum of pressure head and velocity head only

Answer

Energy dissipated per unit length of channel

Question 5

In a pipe network analysis using the Hardy Cross method, what condition must be satisfied at each junction node?

Accepted Answer

Continuity: the algebraic sum of flows at each node must equal zero

Answer

The sum of head losses around each loop must equal zero

Answer

The Reynolds number must be the same in all connecting pipes

Answer

Pressure must be equal in all pipes meeting at a junction

Question 6

A venture meter measures flow rate by detecting the pressure difference between:

Accepted Answer

The inlet section and the constricted throat section

Answer

Two points on the same cross-section at different depths

Answer

The pipe inlet and the pipe outlet

Answer

The pump discharge and the downstream reservoir

Question 7

Cavitation in hydraulic systems is most likely to occur when:

Accepted Answer

Local pressure drops below the vapor pressure of the liquid

Answer

Flow velocity is very low and pressure is very high

Answer

The Reynolds number falls below the laminar threshold

Answer

Pipe diameter is too large relative to the pump capacity