Fluid Mechanics Flashcards
(42 cards)
study of fluids at rest in equilibrium situations
Fluid statics
study of fluids in motion
Fluid mechanics
Application Areas of Fluid Mechanics (7)
- Industrial applications
- Piping and plumbing systems
- Aircraft and spacecraft
- Human body
- Natural flows and weather
- Power plants
- Boats
Intermolecular bonds are strongest in _______ and weakest in __________.
solids
gases
The molecules in a _____ are arranged in a pattern that is repeated throughout.
Solid
In _________ molecules can rotate and translate freely
liquids
In the ____ phase, the molecules are far apart from each other, and molecular ordering is nonexistent
gas
The arrangement of atoms in different phases:
(a) molecules are at relatively fixed positions in a ________ ,
(b) groups of molecules move about each other in the ________ phase, and
(c) individual molecules move about at random in the ______ phase.
a. solid
b. liquid
c. gas
In a liquid, groups of molecules can move relative to
each other, but the volume remains relatively constant
because of the ___________ between the
molecules. As a result, a liquid takes the shape of the
container it is in.
strong cohesive forces
A gas expands until it encounters the walls of the
container and fills the entire available space. This is
because the gas molecules are widely spaced, and the
________________ between them are very small. Unlike
liquids, a gas in an open container cannot form a free
surface
cohesive forces
A _________ is any substance that can flow
fluid
___________ or more precisely, the ______________, of a substance is its mass per unit volume, for a pure substance the density has the same numerical value as is mass concentration. Each materials have different ___________.
Density or Volumetric mass density
is the ratio of the density of a substance to the density of a reference substance;
equivalently, it is the ratio of the mass of a substance to the mass of a reference substance for the same given volume
specific gravity
ratio of an object’s density to the density of water at 4.0 oC
specific gravity (s.g.) or “relative density” = 1000 kg/m3
It is a dimensionless quantity
specific gravity
If a substance’s relative density is less than one then it is ___________ than the reference;
if greater than 1 then it is ________than the reference.
If the relative density is exactly 1 then the densities are _______
less dense
denser
equal
defined as the normal force F per unit area A over which the force is applied.
pressure
Does not require a knowledge of the behavior of individual molecules and provides a direct and easy way to analyze engineering problems
Macroscopic` or classical approach
Based on the average behavior of large groups of individual molecules.
Microscopic or statistical approach
_________ at a point is defined as the normal force per unit area
Pressure
a small surface of area (dA) within a fluid at rest:
The surface does not accelerate, so the surrounding fluid exerts equal _______ forces on both sides of it.
The fluid cannot exert any force parallel to the surface, since that would cause the surface to ______
normal forces
accelerate
The pressure at the top is the_____________.
The pressure at the bottom has the same value p.
The pressure is the same at any two points at the same level.
The shape of the container does not matter.
atmospheric pressure
- pressure of the earth’s atmosphere
- varies with weather changes and with elevation.
atmospheric pressure
At sea level the normal atmospheric pressure is ___ atmosphere (atm) is given by _________ Pa.
1 atm = 1.013x10^5 Pa.
