Chapter 1 Quiz - Fluid Dynamics

mechanics

study of motion

what is a common example of an incompressible fluid?

water

what is a common example of a compressible fluid?

air

what is a fluid?

A substance that flows freely, such as a liquid or a gas

what is the energy contained by the space between molecules?

internal energy

what is normal stress known as in fluid dynamics?

pressure

how does a fluid respond to shear stress?

deforms continuously

In solids, stress is proportional to strain, but in fluids, stress is proportional to

strain rate

Distinction between a solid and a fluid is made on the basis of the substance's ability to _ an applied shear (or tangential) stress.

resist

what is the no-slip condition?

there is no slip between the fluid and the surface

does the no-slip condition result in a boundary layer?

yes

a no-slip fluid is viscous or inviscid?

viscous

A viscous fluid has a boundary layer. T/F?

True, viscous = boundary layer

what defines a fluid as incompressible?

consistent density throughout, if the change in density after being compressed is less than 5%

what is it called when an object's speed is less than the speed of sound?

subsonic

what is it called when an object's speed is greater than the speed of sound?

supersonic

what is it called when an object's speed is equal to the speed of sound?

sonic

what is it called when an object is moving at a speed between 0.9 times the speed of sound and 1.1 times the speed of sound?

transonic

what is the formula for/define mach number?

ratio of speed of flow to speed of sound

Explain laminar vs. turbulent.

laminar: orderly layers of flow, with a thick boundary layer
turbulent: disorderly, high velocity, with a thin boundary layer

what is Reynold's number? (definition, not formula)

a value designating how turbulent a fluid's flow will be, inertial force/viscous force

high vs low RN

high: turbulent, low: laminar

what does it mean when a fluid is classified as viscous?

it is thick, it has a high viscosity

what does it mean when a fluid is classified as inviscid?

it is thin, it has a low viscosity

what kind of force does a viscous fluid create?

resistant, friction, sheer

thick, viscous fluids require (more/less) force to move

more

viscous fluids experience a _ in energy much greater than inviscid fluids

loss

Define and give an example of Internal vs external flows

internal: flowing within something, pipes
external: flowing around something, air/wind

Define and give an example of Steady vs unsteady flows

steady: no change with time, such as a system during normal operation
unsteady: a function of time, a system right after being turned on/off

What is 1D, 2D, & 3D? Compare

Everything in real life is 3D, but we make assumptions, such as setting certain values as constants to make problem solving/calculations easier

Uniform flow is

spatial, with a constant velocity with position

a non-uniform flow has

changes in its velocity

control volume is a(n) ____ system

open

control mass is a(n) ____ system

closed

list the 7 primary dimensions

length, mass, time, temperature, current, light, volume (cllmttv)

give 1 example of a secondary dimension and which 2 primary dimensions it uses

velocity (length over time)

tera, T

10^12

giga, G

10^9

mega, M

10^6

kilo, k

10^3

hecto, h

10^2

deka, da

10^1

deci, d

10^-1

centi, c

10^-2

milli, m

10^-3

micro, μ

10^-6

nano, n

10^-9

pico, p

10^-12

example of an extensive property

mass/volume

example of an intensive property

density, temperature

density is inverse to

specific volume

universal gas constant

8.3145 J/mol K

what is continuum flow

a fluid with no gaps in it

specific gravity

the ratio of the density of a substance to the density of a given reference material

compare the units of temperature (c,k,r)

1 R = 5/9 K, K=C+273.15. 0K=0R=-273.15°C