Civil Engineering Licensure Examinations: Hydraulics and Geotechnical Engineering (April 2025)

Vocabulary flashcards covering key concepts, equations, and terms from the hydraulics and geotechnical topics in the provided lecture notes.

Hydrostatic head

The pressure head produced by the vertical height of a static liquid column; given by γh, used in head computations (e.g., head contributing to a jet’s driving pressure).

Coefficient of velocity (Cv)

Empirical factor in V = Cv√(2gH); Cv = 1.0 for an ideal jet, less than 1 for real nozzles due to losses.

Velocity head

The kinetic-energy component of a fluid's energy per unit weight; equal to V^2/(2g).

Maximum jet height above the center of the orifice

The highest vertical rise of a jet above the orifice center, found from h = V1^2/(2g) where V1 is the vertical component of exit velocity.

Time of flight

Total time a projectile (or jet particle) remains in flight before hitting the ground; found via vertical motion equations.

Horizontal distance (range)

The horizontal distance traveled from the launch point to impact; depends on horizontal velocity and time of flight.

Headloss (hf)

Loss of head (energy) due to friction and minor losses along a pipe or channel.

Friction factor

Dimensionless coefficient in the Darcy–Weisbach equation relating hf to flow length, diameter, and velocity.

Energy gradient slope

Slope of the energy grade line; S = hf/L, the head loss per unit length.

Roughness coefficient

Parameter representing interior surface roughness of a pipe that influences friction losses.

Velocity in a pipe

The speed of fluid flow within a pipe cross-section; used to compute headloss and discharge.

Flow rate (Q)

Volume of fluid passing a cross-section per unit time; Q = A·V.

Cross-sectional area (A)

Area of a pipe’s cross-section; for a circle, A = πD^2/4.

Specific gravity (SG)

Ratio of a substance’s density to the density of water; SG = ρ/ρwater.

Buoyancy

Upward force on a submerged or floating body due to displaced fluid (Archimedes’ principle).

Buoyant force

Upward force exerted by a fluid on an immersed object; Fb = ρfluid·g·V_submerged.

Improvised barometer

A barometer using a liquid of density 0.80 that of mercury to measure atmospheric pressure.

Density ratio (ρHg/ρliq)

Ratio of mercury density to the improvised barometer liquid’s density (≈1.25 when ρliq = 0.8ρHg).

Barometer reading (mmHg equivalent)

Atmospheric pressure reading expressed as a mercury column height (mm Hg) or its equivalent with another liquid.

Height of mountain via improvised barometer

Elevation estimated from barometer readings using hydrostatic relations and density ratios between air and the barometer liquid.

Coefficient of discharge (Cd)

Ratio of actual discharge to theoretical discharge through an orifice; Cd < 1 accounts for losses (e.g., Cd ≈ 0.60 in some problems).

Direct shear test

A simple lab test to determine soil shear strength by shearing two halves of a specimen across a plane.

Tri-axial test

A laboratory test to determine soil shear strength under controlled confining pressure in three directions.

Hydrodynamics

The study of how liquids move and behave under different conditions; branch of fluid mechanics dealing with moving fluids.

Hydrostatic head

The pressure head produced by the vertical height of a static liquid column; given by \gamma h, used in head computations (e.g., head contributing to a jet’s driving pressure).

Coefficient of velocity (Cv)

Empirical factor in V = Cv\sqrt{2gH}; Cv = 1.0 for an ideal jet, less than 1 for real nozzles due to losses.

Velocity head

The kinetic-energy component of a fluid's energy per unit weight; equal to V^2/(2g).

Maximum jet height above the center of the orifice

The highest vertical rise of a jet above the orifice center, found from h = V1^2/(2g) where V1 is the vertical component of exit velocity.

Time of flight

Total time a projectile (or jet particle) remains in flight before hitting the ground; found via vertical motion equations.

Horizontal distance (range)

The horizontal distance traveled from the launch point to impact; depends on horizontal velocity and time of flight.

Headloss (hf)

Loss of head (energy) due to friction and minor losses along a pipe or channel.

Friction factor

Dimensionless coefficient in the Darcy–Weisbach equation relating hf to flow length, diameter, and velocity.

Energy gradient slope

Slope of the energy grade line; S = h_f/L, the head loss per unit length.

Roughness coefficient

Parameter representing interior surface roughness of a pipe that influences friction losses.

Velocity in a pipe

The speed of fluid flow within a pipe cross-section; used to compute headloss and discharge.

Flow rate (Q)

Volume of fluid passing a cross-section per unit time; Q = A\cdot V.

Cross-sectional area (A)

Area of a pipe’s cross-section; for a circle, A = \pi D^2/4.

Specific gravity (SG)

Ratio of a substance’s density to the density of water; \text{SG} = \rho/\rho_{\text{water}}.

Buoyancy

Upward force on a submerged or floating body due to displaced fluid (Archimedes’ principle).

Buoyant force

Upward force exerted by a fluid on an immersed object; Fb = \rho{\text{fluid}}\cdot g\cdot V_{\text{submerged}}.

Improvised barometer

A barometer using a liquid of density 0.80 that of mercury to measure atmospheric pressure.

Density ratio (\rho{\text{Hg}}/\rho{\text{liq}})

Ratio of mercury density to the improvised barometer liquid’s density (\approx 1.25 when \rho{\text{liq}} = 0.8\rho{\text{Hg}};).

Barometer reading (mmHg equivalent)

Atmospheric pressure reading expressed as a mercury column height (mm Hg) or its equivalent with another liquid.

Height of mountain via improvised barometer

Elevation estimated from barometer readings using hydrostatic relations and density ratios between air and the barometer liquid.

Coefficient of discharge (Cd)

Ratio of actual discharge to theoretical discharge through an orifice; Cd < 1 accounts for losses (e.g., Cd \approx 0.60 in some problems).

Direct shear test

A simple lab test to determine soil shear strength by shearing two halves of a specimen across a plane.

Tri-axial test

A laboratory test to determine soil shear strength under controlled confining pressure in three directions.

Hydrodynamics

The study of how liquids move and behave under different conditions; branch of fluid mechanics dealing with moving fluids.

Specific weight (\gamma)

The weight per unit volume of a fluid, typically expressed in units like \text{N/m}^3 or \text{lb/ft}^3. It is related to density (\rho) by the equation \gamma = \rho g, where g is the acceleration due to gravity.

Darcy–Weisbach Equation

An empirical equation that calculates the major head loss (friction loss) in a pipe: h_f = f \frac{L}{D} \frac{V^2}{2g}, where f is the friction factor, L is pipe length, D is pipe diameter, V is fluid velocity, and g is acceleration due to gravity.

Archimedes’ Principle

States that the buoyant force on a submerged or floating object is equal to the weight of the fluid displaced by the object.