Studied by 2 peoplemechanics
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
Note 
Flashcard (63)