Compressible Fluid

The basic information about the compressible fluid.

1. C OMPRESSIBLE F LOW 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. Introduction

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. Perfect G as Equation

5. Basic Thermodynamic processes

6. 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).

7. The momentum per second known as momentum flux. The momentum = (mass flow rate)(velocity of flux fluid) =(mass per second)(velocity) = AV (V) Momentum Equation  

8. 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. Pressure wave propagation and sound velocity

9. Types of Waves