fluid mech Flashcards
Fluid mechanics
A branch of Mechanics
which focuses on the behavior of fluids at rest or in motion,
and the interaction of fluids with solids or
other fluids at the boundaries.
Fluid Mechanic
Studies the motion of
incompressible fluids
Hydrodynamics
a subcategory of hydrodynamics
that deals with liquid flows within pipes and
open channels.
Hydraulics
deals with the flow of fluids
that undergo significant density changes,
such as the flow of gases through nozzles at
high speeds.
Gas Dynamics
is the force per unit area
determined by dividing the force by the
area upon which it acts
stress
refers to the normal
component of a force acting on a surface
per unit area
normal stress
is the tangential component
of a force acting on a surface per unit
area
shear stress
the normal stress
experienced by a fluid at rest
pressure
The vapor phase of a substance is
customarily called ____ when it is
above the critical temperature
A gas
implies that the current phase is
not far from a state of condensation.
vapor
flow region adjacent to
the wall in which the viscous effects (and
thus the velocity gradients) are significant
Boundary Layer
the force a fluid exerts on a surface in the flow
direction
Surface drag or skin friction drag
fluid and a solid surface have the same
temperature at the points of contact
no-temperature-jump condition
is a measure of internal stickiness of the
fluid caused by cohesive forces between the
molecules in liquids and by molecular collision in
gases.
Viscosity
Flows in which the frictional
effects are significant
Viscous flows
regions (typically regions
not close to solid surfaces) where viscous forces
are negligibly small compared to inertial or
pressure forces
Inviscid flow regions
The flow of an unbounded fluid
over a surface such as a plate, a wire, or a pipe;
viscous effects are limited to boundary layers
near solid surfaces and to wake regions
downstream of bodies.
External flow
fluid is bounded by solid
surfaces; dominated by viscous effects
throughout the flow fields.
Internal flow
flow of liquids in a duct that
is only partially filled with the liquid, forming a free
surface.
Open-channel flow
the density remains
nearly constant throughout; the volume of
every portion of fluid remains unchanged over
the course of its motion
Incompressible flow
a dimensionless number
used to approximate and model gas flows as
incompressible
Mach number
the highly ordered fluid motion
characterized by smooth layers of fluid; e.g., The
flow of high-viscosity fluids such as oils at low
velocities
Laminar flow
the disordered fluid motion
typically occurring at high velocities and
characterized by velocity fluctuations; the flow of
low-viscosity fluids such as air at high velocities
Turbulent flow
a flow that alternates
between being laminar and turbulent.
Transitional flow
is the key parameter for the
determination of the flow regime in pipes
Reynolds Number
if a fluid is forced to flow over a
surface or in a pipe by external means such as
a pump or a fan.
Forced flow
fluid motion is due to natural
means such as the buoyancy effect, which
manifests itself as the rise of warmer (and thus
lighter) fluid and the fall of cooler (and thus
denser) fluid.
Natural flow
can be closely approximated by
devices that are intended for continuous operation
can be closely approximated by
devices that are intended for continuous operation
states that the net heat energy supplied to the system is equal to sum of change in internal energy of the system and work done by the system. This means that heat energy cannot be created or destroyed.
first law of thermodynamics
any device that will have a continuous flow of material through it. Some examples of steady flow devices include pipes, nozzles, diffusers, and pumps. Generally the material flowing through the device is a gas or liquid, and if the device in any way changes the velocity of the fluid then that fluid will exert a force
steady flow device
can exchange both energy and matter with its surroundings.
open system
