ASCE Hydraulics and Fluid Mechanics 3

Question 1

The specific weight of water (γ) at standard conditions (68°F/20°C) is approximately:

Accepted Answer

62.4 lb/ft³ (9.81 kN/m³)

Answer

Water at standard conditions has a specific weight of approximately 62.4 lb/ft³ (9,810 N/m³ or 9.81 kN/m³), which is used extensively in hydrostatic pressure and buoyancy calculations.

Question 2

The force exerted by a static fluid on a submerged flat surface acts at the:

Accepted Answer

Center of pressure, which is always at or below the centroid

Answer

The resultant hydrostatic force acts at the center of pressure, which is located at or below the centroid because pressure increases with depth, weighting the force distribution toward the lower portion of the surface.

Question 3

The Moody diagram is used to determine which parameter in the Darcy-Weisbach equation?

Accepted Answer

The Darcy-Weisbach friction factor (f)

Answer

The Moody diagram relates the Darcy-Weisbach friction factor (f) to the Reynolds number and relative roughness (ε/D), enabling engineers to determine f for both laminar and turbulent pipe flow conditions.

Question 4

In the design of a spillway, the discharge coefficient (Cd) is used to account for:

Accepted Answer

Hydraulic losses and velocity of approach effects on actual flow

Answer

The discharge coefficient Cd accounts for real-fluid effects including friction losses, velocity of approach, and crest geometry, correcting the theoretical weir formula Q = CLH^(3/2) to match actual measured discharge.

Question 5

Which type of flow profile in open channels is classified as M1 (Mild slope, profile 1)?

Accepted Answer

Flow depth greater than normal depth on a mild slope

Answer

An M1 profile occurs on a mild slope (normal depth > critical depth) when the actual flow depth exceeds normal depth, causing the water surface to back up as in a backwater curve behind a dam or obstruction.

ASCE - American Society of Civil Engineers Certification Practice Test

ASCE - American Society of Civil Engineers Certification Practice Test

ASCE Hydraulics and Fluid Mechanics 3