1) Compressible flow is when the density of a fluid changes during flow, such as gases. Incompressible flow assumes constant density, such as liquids. 2) Examples of compressible flow include gases through nozzles, compressors, high-speed projectiles and planes, and water hammer. 3) Bernoulli's equation relates pressure, temperature, and specific volume and only applies to steady, incompressible flow without friction losses along a single streamline.

1. Dhaval Jalalpara A.

2.  Incompressible Flow
In this fluid ,the density of the
flowing fluid is constant during the process of
flow
 Compressible Flow
In this fluid ,the density of fluid does
not remain constant during the process of flow.
In other words the density of the fluid changes
from point to point in compressible flow.

3. All real fluid are compressible fluid flow.
But in some cases, i.e. flow of liquids which undergo
only small changes in density even over wide range
of velocity and pressure changes. Hence liquid flow
can be assumed incompressible fluid flow.
Example of compressible flow.
(1) Flow of gases through nozzles and orifices.
(2) Flow of gases in compressors.
(3) The flight of projectiles and aero planes
moving at high altitude with high velocity.
(4) Water hammer and acoustics.

4. It is defined as the equation which
gives the relationship between the pressure,
temperature and specific volume of a gas.

13. Bernoullis’s equation has some restriction
in its applicability , they are:
 Flow is steady;
 Density is constant (which also means the fluid is
incompressible);
 Friction losses are negligible
 The equation relates a state at the two point along
a single streamline,(not condition on two different
streamline).

14.  The momentum per second known as
momentum flux.
The momentum = (mass flow rate)(velocity of
flux fluid)
=(mass per second)(velocity)
= AV (V)𝝆

15.  The disturbance in a solid, liquid or gas is
transmitted from one point to another point .
 The disturbance creates the pressure waves
in a fluid.
 The pressure waves move a velocity of sound
waves in all directions.
Consider a one-dimensional flow
through long straight rigid pipe having uniform
cross sectional area . The frictionless piston
fitted at one end of a pipe as shown in Fig.