hge Flashcards
(120 cards)
1
Q
What is density defined as?
A
Mass per unit volume.
2
Q
What is the reciprocal of density called?
A
Specific volume.
3
Q
What is specific gravity (SG)?
A
The ratio of the density of a substance to the density of a standard substance at a specified temperature.
4
Q
What is the standard substance for measuring specific gravity?
A
Water at 4°C.
5
Q
What is the formula for specific weight (weight density)?
A
γs = ρg.
6
Q
What is the ideal-gas equation of state?
A
P = ρRT.
7
Q
What does the variable T represent in the ideal gas equation?
A
Thermodynamic (absolute) temperature.
8
Q
What is the relationship between pressure and volume for an ideal gas at constant temperature?
A
P2V1 = P2V2.
9
Q
What does the bulk modulus of compressibility (k) represent?
A
The change in pressure corresponding to a fractional change in volume or density of the fluid.
10
Q
What phenomenon is characterized by a sound resembling a hammer when a liquid encounters an abrupt flow restriction?
A
Water hammer.
11
Q
What is viscosity?
A
The internal resistance of a fluid to motion or the ‘fluidity’.
12
Q
What is kinematic viscosity (ν)?
A
The ratio of dynamic viscosity (μ) to mass density (ρ).
13
Q
What causes surface tension in a fluid?
A
Intermolecular cohesive forces.
14
Q
What is capillarity?
A
The behavior of liquid in a thin-bore tube caused by surface tension.
15
Q
Fill in the blank: Pressure is defined as a normal force exerted by a fluid per unit _______.
A
Area.
16
Q
What is pressure head?
A
The height of a column of homogeneous liquid that produces an intensity of pressure.
17
Q
What is the formula for converting pressure head from liquid A to liquid B?
A
P = (SG a / SG b) * h.
18
Q
What is gage pressure?
A
Pressure above or below atmospheric pressure.
19
Q
What is Archimedes’ Principle?
A
The buoyant force on an object is equal to the weight of the fluid it displaces.
20
Q
What is the formula for buoyant force (BF)?
A
BF = γliq * Vdisplaced.
21
Q
What is the effect of fluid density on buoyancy?
A
The density of the fluid affects the buoyant force.
22
Q
What happens when the density of the object is less than the fluid?
A
The object rises (wholly immersed).
23
Q
What is the formula for the hydrostatic force on a curved surface?
A
F = F_H^2 + F_V^2.
24
Q
What are the types of dams mentioned?
A
- Gravity Dams
- Embankment Dams
- Arch Dams
- Buttress Dams
25
What is the purpose of a dam?
* Irrigation and drinking water
* Power Supply (Hydroelectric)
* Navigation
* Flood Control
* Multi-Purpose
26
What is the relationship between pressure and elevation difference in fluids?
P2 - P1 = γh.
27
What is the formula for the total hydrostatic force on a plane surface?
F = pA.
28
What is the significance of the metacentric height in buoyancy?
It helps determine the stability of floating bodies.
29
What happens to an object when its density is equal to that of the fluid?
It achieves neutral buoyancy (wholly immersed).
30
What is the formula for pressure in a moving vessel with horizontal motion?
tan(θ) = a / g.
31
What does the term 'specific weight' refer to?
The weight of a unit volume of a substance.
32
What is the formula for the tangent of the angle in vertical motion?
tanθ = aH/g
## Footnote
Use (+) for upward motion and (-) for downward motion.
33
What forces act at a point h below the liquid surface?
* Weight of the liquid above the point, γV
* Inertia force, Ma
* Pressure force, F = pA
34
What is the pressure formula in vertical motion?
p = γ(1 ± a/g)
## Footnote
Use (+) for upward motion and (-) for downward motion.
35
In rotating vessels, how is the slope of the paraboloid calculated?
tanθ = ω²x/g
## Footnote
Where ω = speed of rotation (radian per second), x = distance from the center of rotation to point of analysis (Radius), g = gravitational acceleration (m/s²).
36
What is the formula for the height of a paraboloid in rotating vessels?
y = (ω²x²)/(2g)
## Footnote
Where ω = speed of rotation (radian per second), x = distance from the center of rotation to point of analysis (Radius), g = gravitational acceleration (m/s²).
37
What does kinetic energy (velocity head) in fluid dynamics represent?
The ability of the fluid mass to do work by its velocity.
38
What is the formula for kinetic energy (Velocity Head)?
K.E. = v²/(2g)
39
Define potential energy (elevation head) in fluid dynamics.
The energy possessed by the fluid by its position or elevation with respect to a datum plane.
40
What is the formula for potential energy (pressure head)?
h = P/γ
41
What is the total flow energy (E) in fluid flow?
E = K.E. + P.E. = v²/(2g) + P/γ + z
42
What is power in the context of fluid dynamics?
Power is the rate at which work is done.
43
How is power efficiency (η) calculated?
η = P out / P in × 100
44
What is Bernoulli’s energy theorem?
E1 + Eadded - Elost/extracted = E2
45
What does the term 'discharge' or 'flow rate' (Q) refer to?
The amount of fluid passing through a section per unit of time.
46
What is the formula for volume flow rate (Q)?
Q = Av
47
What is the relationship between mass flow rate (M) and weight flow rate (Wf)?
* Wf = γQ
* M = ρQ
48
What does the energy possessed by a flowing fluid consist of?
Kinetic and potential energy.
49
What is the energy equation with head lost?
E1 - HL1-2 = E2
50
What is the formula for total head in fluid dynamics?
H = h + A + A - B
51
What is the equation for theoretical velocity in fluid dynamics?
vt = √(2gH)
52
What is the coefficient of discharge (Cd)?
The ratio of the actual discharge through the device to the ideal or theoretical discharge.
53
What does the coefficient of velocity (Cv) represent?
The ratio of the actual mean velocity to the ideal or theoretical velocity.
54
Define the coefficient of contraction (Cc).
The ratio of the actual area of the contracted section of the stream or jet to the area of the opening.
55
What is an orifice in fluid dynamics?
An opening (usually circular) with a closed perimeter through which fluid flows.
56
What is a weir?
An overflow structure built across an open channel for measuring or controlling the flow of liquids.
57
What is the formula for discharge through a rectangular weir?
Q = 2C√(2gL)(H + h - h)
58
What is the significance of the Francis formula?
It relates to the flow through orifice, weirs, or tubes under steady conditions.
59
What is the formula for contracted rectangular weir?
Cw = 1.84
60
What is the formula for a triangular weir (V – Notch)?
Q = 4C√(2gLH) / 15
61
What are Cipolletti weirs?
Trapezoidal weirs with a side slope of 1 horizontal to 4 vertical.
62
What is the relationship between Qin and Qout in steady flow?
Qout = Qin
63
Define dynamic force in fluid flow.
F = ρQ(v1 - v2)
64
What does porosity (n) represent?
Volume of void / Total volume
65
What is the formula for the void ratio (e)?
e = Volume of void / Volume of solid
66
What does the water content (ω) in soil indicate?
Weight of water / Weight of solid × 100
67
What is the degree of saturation (S)?
S changes from 0% for completely dry soil to 100% for fully saturated soil.
68
What is the critical hydraulic gradient (i_cr)?
i_cr = γb / (Gs - 1) / (1 + e)
69
What does specific gravity (G) represent?
G = unit weight of solid / unit weight of water
70
What is the formula for total specific energy in a channel?
E = h + v²/(2g)
71
What is the Froude number (F)?
F = v / √(gD)
72
What does a hydraulic jump signify?
An abrupt increase in depth of rapidly flowing water.
73
What is the formula for relative density of granular soils?
S = (Vw / Vv) × 100
## Footnote
Vw is the volume of water, and Vv is the volume of voids.
74
What does the specific gravity (G) of soil represent?
G = γs / γw
## Footnote
γs is the unit weight of the solid, and γw is the unit weight of water.
75
What is the formula for total unit weight (γ)?
γ = W / V
## Footnote
W is the total weight, and V is the total volume.
76
Define dry unit weight (γd).
γd = Ws / V
## Footnote
Ws is the weight of solids.
77
What is the formula for the shrinkage ratio (SR)?
SR = (1 m² / ρW) × V2
## Footnote
ρ is the density.
78
What is the equation for degree of saturation?
S = (γd / γm) × (1 + ω)
## Footnote
ω is the water content.
79
What are Atterberg's Limits?
Limits defining the consistency of soil, including Liquid Limit (LL), Plastic Limit (PL), and Shrinkage Limit (SL).
## Footnote
They indicate the state of soil behavior at different moisture contents.
80
How is plasticity index (PI) calculated?
PI = LL - PL
81
What does a liquidity index (LI) of less than 0 indicate?
Brittle solid
82
What is the formula for consistency index (CI)?
CI = (LL - ω) / (LL - PI)
83
What is the liquid limit (LL)?
The water content at which soil changes from plastic to liquid state.
84
What does the toughness index (TI) measure?
TI = PI / FI
## Footnote
FI is the flow index.
85
What are the sizes for different soil particles according to USDA classification?
* Gravel: > 2mm
* Sand: 2mm – 0.05mm
* Silt: 0.05mm – 0.002mm
* Clay: < 0.002mm
86
Define effective size (D10) in soil classification.
The diameter corresponding to 10% finer in particle size distribution.
87
What does the uniform coefficient (Cu) represent?
Cu = D60 / D10
88
What is the formula for coefficient of gradation (Cc)?
Cc = (D30²) / (D60 × D10)
89
What is the formula for buoyant unit weight (γb)?
γb = γsat - γw
90
What does Darcy's Law describe?
The flow of fluid through a porous medium.
91
What is the formula for hydraulic gradient (i)?
i = Δh / L
92
What is Bernoulli's equation?
h = γ + (v² / 2g) + z
93
How is permeability (k) calculated in a constant head test?
k = (VL) / (Aht)
## Footnote
V is the volume collected, t is the time of collection.
94
What does the falling-head test measure?
k = (aL / At) × ln(h1 / h2)
95
What is the formula for transmissivity (T) in aquifers?
T = kb
96
How is equivalent hydraulic conductivity calculated in stratified soil?
kH(eq) = (k1H1 + k2H2 + k3H3) / (H1 + H2 + H3)
97
What is the basic settlement formula?
σ = (3Q / (2πz²))
98
What is the significance of flow nets in soil mechanics?
They represent the flow of water through soil graphically, showing flow lines and equipotential lines.
99
What is the relationship between discharge velocity (v) and hydraulic conductivity (k)?
v = ki
## Footnote
i is the hydraulic gradient.
100
What does 'r' represent in the basic settlement formula?
The horizontal distance between an arbitrary point P below the surface and the vertical axis through the point load Q.
101
What is 'z' in the context of the basic settlement formula?
The vertical depth of point P from the surface.
102
What is the Boussinesq stress coefficient IB?
IB = (3/2π) * (1 + (r/z)^2)^(-5/2)
103
What is Westergaard's formula for point loads?
σ = (Q / (2πz)) * (1 + (r/z)^2)^(-2)
104
In primary consolidation settlement, what does Cc represent?
Compression index.
105
What is the formula for primary consolidation settlement of normally consolidated fine-grained soils?
ΔH = H * (Cc / (1 + eo)) * log((P + ΔP) / Po)
106
What distinguishes over-consolidated fine-grained soils in primary consolidation?
For over-consolidated soils, Po + ΔP < Pc.
107
What is the swell index denoted as Cs?
Cs = swell index.
108
What does OCR stand for?
Over-consolidation ratio.
109
What is the formula for general shear failure in rectangular footing?
q = cN * (1 + 0.3B/L) + qN + 0.5γBN.
110
What is the formula for local shear failure in strip footing?
q = c'N' * (1 + 0.3B/L) + qN' + 0.5γBN' * (1 - 0.2B).
111
How is the average degree of consolidation (U) calculated?
U = ΔH / ΔHmax.
112
What is the coefficient of volume compressibility (mv)?
mv = Δe / (ΔP * (1 + eo)).
113
What does the Rankine's active coefficient (Ka) formula look like?
Ka = (1 - sin(φ)) / (1 + sin(φ)).
114
What is the formula for Coulomb's active coefficient (inclined backfill)?
Ka = sin²(β + φ) / (sin²β * sin(β - δ)).
115
What is the factor of safety against sliding without pore water pressure?
F.S. = c / (γH cos²β tan β + tan φ).
116
What does the ultimate bearing capacity of piles (qb) depend on?
qb = cNc * Atip.
117
What is the efficiency of group piles (E) formula?
E = 2(m + n - 2)S + 4D / (πDmn).
118
Fill in the blank: The coefficient of at rest earth for normally consolidated soils is _______.
Ko = 1 - sin(φ).
119
True or False: The direct shear test allows soil to fail along its weakest plane.
False.
120
What is the relationship between effective stress and lateral stress in soil mechanics?
Lateral stress = Ka * pe.
