FORMULAS FOR FLUID MECHANICS

Question 1

Mass Density

Answer 1

ρ = M/V

Question 2

Density for ideal gas

Answer 2

ρ = P/RT

Question 3

What is R?

Answer 3

gas constant

Question 4

Values of R

Answer 4

287 j/kg K
1716 lb ft/slug R

Question 5

Kelvin=

Answer 5

C + 273

Question 6

Rankine=

Answer 6

F + 460

Question 7

Specific Volume

Answer 7

Vs = 1/ρ =V/M

Question 8

Unit weight

Answer 8

γ =W/V = ρg

Question 9

Specific Gravity

Answer 9

Sg= P(liquid or gas)/P(water or air)

Question 10

Values for the unit weight of water

Answer 10

62.4 lb/ft^3
9.81 kN/m^3

Question 11

Values for Density of water

Answer 11

1.94 slugs/ft^3
1000 kg/m^3

Question 12

Specific gravity of water

Answer 12

1

Question 13

Viscosity

Answer 13

µ = τ/(dv/dy)

Question 14

Kinematic Viscosity

Answer 14

V = µ/P

Question 15

Surface tension (pressure inside a droplet of liquid)

Answer 15

P = (4σ)/d

Question 16

Capillarity

Answer 16

h = 2Tcosθ/ρgr = 4σcosθ/γd

Question 17

Compressibility

Answer 17

β = (-ΔV/V)/ΔP = 1/Eb

Question 18

Bulk Modulus of Elasticity

Answer 18

Eb = stress/strain = ΔP/(-ΔV/V)

Question 19

Pressure Disturbances

Answer 19

C = √(Eb/ ρ) = √(1/βρ)

Question 20

Property changes in ideal gas

Answer 20

P1V1/T1=P2V2/T2

Question 21

Boyle’s Law

Answer 21

P1V1 = P2V2

Question 22

Pressure!

Answer 22

P = F/A

Question 23

Absolute Pressure

Answer 23

P(abs) = P(gage) + P(atm)

Question 24

Gage Pressure

Answer 24

P(gage) = Pm
P(gage) = Σρgh = Σγh

Question 25

Atmospheric Pressure

Answer 25

P(atm) = 1 barometric pressure
P(atm) = 101.325 kPa
P(atm) = 1.03323 kg/cm^3 = 14.696 lb/in^2 = 760 mm hg

Question 26

CHANGE IN PRESSURE

Answer 26

P2 - P1 = γh
P2 = P1 + γh

Question 27

Pressure Head

Answer 27

h = P/γ

Question 28

Conversion of pressure head

Answer 28

hB = hA (GsA/GsB)

Question 29

Pressure below layers of different liquids

Answer 29

P(bottom) = Σγh + p