Lecture 1-2

Question 1

Fluids are

Answer 1

substances in the liquid or gas phase

Question 2

Normal stress is

Answer 2

force on surface per unit area, orthognal to the plane/normal component

Question 3

Shear stress is

Answer 3

force on a surface per unit area, parrallel to the plane/tangential component

Question 4

Pressure is

Answer 4

normal stress in fluid at rest

Question 5

Solids resist an applied shear stress by

Answer 5

deforming

Question 6

Fluids —- —— under applied shear stress

Answer 6

deform continuously

Question 7

Laminar flow is

Answer 7

highly ordered fluid motion, organised by smooth layers of fluid

Question 8

Turbulent flow is

Answer 8

random chaotic fluid motion characterised by velocity fluctuations

Question 9

Transitional flow is

Answer 9

a mix of laminar and turbulent flow

Question 10

Re =

Answer 10

ρ V L / µ

fluid density x Volume x characteristic length / fluid viscosity

Reynold’s number

Question 11

A laminar flow is characterised by a —- µ and —- V

Answer 11

high, low

Question 12

A turbulent flow is chracterised by a —- μ and a —- V.

Answer 12

low, high

Question 13

Intensive fluid properties are … 3 egs

Answer 13

properties that are independent of the mass of the fluid in a system

pressure temperature density

Question 14

Extensive fluid properties are … 3 egs

Answer 14

properties that are dependent on the amount of fluid in the system

volume momentum energy

Question 15

Specific fluid properties are

Answer 15

extensive fluid properties per unit mass

Question 16

Specific energy =

Specific volume =

Answer 16

energy per unit mass

volume per unit mass

Question 17

A control volume is

Answer 17

a small selected region in a space which represents the behaviours of the whole system

Question 18

Density is

SI units

Answer 18

mass per unit volume

kg m^-3

Question 19

SI units specific volume

Answer 19

m^3 kg^-1

Question 20

Specific weight is

SI units

Answer 20

Weight per unit volume

N/m^3

Question 21

Density and volume have what sort of relationship

Answer 21

Inversely proportional

Question 22

Coefficient of compressibility or bulk modulus measures

Answer 22

the relative change of density or volume for a given pressure change (at a constant temp)

Question 23

Coefficient of compressibility is represented with

Answer 23

small K

Question 24

small K = (both density and volume)

Answer 24

Coefficient of compressibility =

d P / ( d ρ / ρ )
change in pressure / (change in density / initial density)

• d P / ( d V / V )
• change in pressure / (change in volume / initial volume)

Question 25

Coefficient of volume expansion measures

Answer 25

the relative change of density or volume for a given temperature change (at P = 0)

Question 26

Coefficient of volume expansion is represented with

Answer 26

β

Question 27

β = (volume and density)

Answer 27

Coefficient of volume expansion =

(d V / V) / d T
(change in volume / initial volume) / change in temp

• (d ρ / ρ) / d T
• (change in density / initial density) / change in temp

Question 28

Dynamic viscosity measures

Answer 28

resistance of deformation of a fluid as a ratio of shear stress and strain rate

Question 29

Dynamic viscosity is represented with a

Answer 29

μ

Question 30

Corn flour is an example of a —– fluid

Answer 30

non-newtonian fluid

Question 31

Honey is an example of a —– fluid

Answer 31

newtonian fluid

Question 32

Strain in dynamic viscosity = deformation =

Answer 32

change in distance of top plate / the distance bwteen the two plates