now we’ll start with the topic of fluid
dynamics. in this topic, we are going to study,
and analyze, motion of fluids. so complete
analysis and study of fluids in motion is
termed as fluid dynamics. very 1st thing we’ll
be taking up the basics of fluid dynamics,
and some situations in which we analyze ideal
fluids. and in some situations we analyze
real fluids. so we can say for basic analysis,
we use, ideal fluids, instead of real fluids,
as real fluids have several limitations. and,
to take it as an ideal fluid, we make, some
to real fluids it can be taken as ideal. like,
the very 1st point about ideal fluid is, stream
line flow. we assume that a fluid flow in
a streamlined manner and streamline flow is
also termed as, laminar flow. this is the
situation in which, a point or we can say
when a fluid body is flowing then we can say,
at a point, velocity of fluid particles, does
when fluid particles are passing, at a specific
point the velocity in magnitude and direction
always remain constant. such kind of flow
we term as, stream line flow. in later part
of this section we’ll discuss about, streamline
representation also. let’s first take up
the 2nd point, which is incompressible flow.
if we talk about incompressible flow, here
we can say, we assume that, during flow, fluid
density, remain constant. whereas in case
of real fluids, it happens that at some point,
fluid density is more and at some point fluid
density is less, but for idealistic situation
we assume that, fluid flow is incompressible,
it remains constant or we assume that fluid
density remains constant throughout the flowing
body. another point we use for this is, non-viscous
flow, as we already discussed about viscosity
of fluid, so we can say, in viscosity, it
is accounting the friction between, different
layers of the fluid. so we can say, for an
ideal fluid, we neglect the viscosity between
layers. in detail, we are going to discus
viscosity in the separate chapter of, properties
of matter or viscous forces. so we can say,
for ideal fluids, we neglect, viscous forces,
between fluid layers. and, last point related
to an ideal fluid assumption is, irrotational
flow. if we talk about an irrotational flow
we can say, here we assume, that fluid particles,
do not impart, any rotational motion, to the
uniform bodies, in path of, fluid, which are
flowing, or we can say which are moving, along
with fluid. and, this happens only when in
a given cross section fluid velocity can be
taken a constant. so we can say, when we talk
about fluid dynamics and we consider ideal
fluids, for ideal fluids we can simply state,
ideal fluid is the 1 in which always it flows
in streamlines, it is incompressible, it is
non viscous, and its flow can be regarded
as irrotational flow. whereas in real fluids,
these properties are not exactly matching.
these are deviated depending on, the parameters
given for a fluid. so, you must be careful
about all these assumptions, as we are going
to use these assumptions, for different cases
in this particular topic.
