Fluid Flow - Definition, Types, Example, FAQs

Q: What is fluid mechanics?

Fluid mechanics definition can be given as the branch of physics that deals with fluid statics and fluid dynamics. The subject which deals with the behavioural study on fluid and its forces are known as fluid mechanics.

Q: What is fluid statics?

The study of fluid at rest and fluid in equilibrium state is known as hydrostatics or fluid statics.

Q: What is the classification of fluids?

Based on their properties, they are different types of fluid. They are listed below Ideal fluid, Real fluid, Newtonian Fluid, Non Newtonian Fluid, Ideal Plastic fluid, Incompressible fluid and compressible fluid.

Q: Give some examples of compressible and incompressible fluids.

Incompressible fluid example: The liquids which have low compressibility like water, petrol, oil are examples of incompressible fluid. Compressible fluid example: Air and Vapour have higher compressibility than other liquids, so they are the best examples of compressible fluids.

Fluid Flow - Definition, Types, Example, FAQs

Edited By Vishal kumar | Updated on Sep 24, 2024 06:45 PM IST

Fluid flow is a topic of fluid mechanics which deals with the subject fluid dynamics. Let us understand the fluid flow process by answering the questions like what is fluid, what is the meaning of fluid, meaning of flow, what are the types of fluid and types of flow.
Fluid flow includes the fluid motion due to some unbalanced force. Until external unbalanced forces are applied to the motion of the fluid, the fluid will continue its motion. Fluid is the matter of substances which do not have any fixed shape and are subjected to external pressure. To understand the meaning of fluid, let's see the examples of fluids: water, honey,blood, air and so on.The main feature of the fluid is their flowing ability. Now, let's see what is flowing? The flow is known as the movement of the fluid from one point to the other.

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Fluid Flow - Definition, Types, Example, FAQs

According to the natural properties of the fluid, there are different types of fluid such as Ideal fluid, Real fluid, Newtonian Fluid, Non Newtonian Fluid, Ideal Plastic fluid, Incompressible fluid and compressible fluid. Let us discuss them in detail.

Ideal Fluid:

An ideal fluid is defined as the fluid which cannot be compressed and also does not contain any viscosity..This is an imaginary fluid used only for mathematical calculations. Other than that, this fluid does not exist in reality. They have a constant density. They possess irrotational motion which have smooth flow. They do not have any internal friction and have steady flow.

Real Fluid:

All the fluids of the real world which contain viscosity are known as real fluids. They are also called practical fluids.

Newtonian fluid:

A Newtonian fluid is defined as the fluid which obeys the laws of Newton of Viscosity. Some Newtonian fluid examples : Water and Gasoline.

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Non Newtonian fluid:

These fluids are opposite to Newtonian fluid. This fluid does not obey the laws of Newton of Viscosity. Non newtonian fluid example: Ketchup

Ideal Plastic fluid:

For an ideal plastic fluid, the shear stress has a proportionality with the velocity gradient. The shear stress will be more than the yield value.

Incompressible fluid:

When the fluid is subjected to any kind of external force, the density properties of the fluid does not change and this kind of fluid is known as incompressible fluid. Incompressible fluid example: Water.

Compressible fluid:

When the fluid is subjected to any kind of external force, the density properties of the fluid will change and this kind of fluid is known as compressible fluid.Compressible fluid examples: Gas , vapour.

Velocity gradient

The Fluid flow is categorized into different types considering different properties like steadiness, viscosity, compressibility, rotational property and so on. They are categorized as below,

NCERT Physics Notes:

Based on their steadiness:

The velocity of the fluid decides the steadiness of the fluid flow.

Steady flow: When the velocity of the fluid is constant, the fluid flow is found to be steady.
UnSteady flow: When the velocity of the fluid varies from time to time, the fluid flow is found to be unsteady.

Based on their Viscosity:

The fluid is classified into viscous and non viscous fluid.

Viscous fluid: The term Viscosity is known as the measurement of the fluid thickness and the fluid with the viscosity is known as viscous fluid.
Non Viscous Fluid: A fluid having no viscosity is known as non viscous fluid.

Based on their compressibility:

On the basis of Mach number, flows are classified into compressible and incompressible fluid.

Incompressible fluid flow have the mach number M < 0.3
Compressible fluid flow have the mach number M between 0.3 to 1

Related Topics Link,

Equation of fluid flow:

The mass flow rate of the fluid flow is defined as the rate of massive fluid movement through a unit area. It is considered to be movement of mass of fluid per unit time. Mathematically, the mass flow rate of the fluid can be written as

M= ρAV,

where ρ denotes the density of the fluid, A denotes the area of the fluid cross section and V represents the velocity of the fluid flow. Thus, the equation infers that the mass flow rate of fluid is proportional to density, area and velocity of the fluid.

Applications of fluid statics in real life:

There are many applications of fluid statics in real life, the main application is it is used in the calculation and measurement of pressure of liquid in the field of hydrostatics like finding the pressure of floating and submerged bodies, pressure of water flow in water dams and gates, and water flow pressure in some liquid storage tanks of homes.

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Applications of fluid dynamics in real life

There are huge application in fluid dynamics, let us discuss the few application below:

It is used to calculate and find the different types of forces and moments in the field of aircraft,
It is used to determine the mass flow rate of petroleum or other gases through pipelines.
Even they are used to predict the weather patterns,
It is used to understand and analyse the nebulae in interstellar space
The use of fluid dynamics also plays a role in modelling different fission weapon detonation.

Hope this article helped you to understand flow of liquid, what is fluid dynamics,fluid flow operation different types of fluids and classification of fluid flow and also identify the difference between the terminologies like difference between rotational and irrotational flow, real and ideal fluid, steady flow and unsteady flow, compressible and incompressible flow and so on. Also check-

Frequently Asked Questions (FAQs)

1. What is fluid mechanics?

Fluid mechanics definition can be given as the branch of physics that deals with fluid statics and fluid dynamics. The subject which deals with the behavioural study on fluid and its forces are known as fluid mechanics.

2. What is meant by fluid?

Fluid is the matter of substances which do not have any fixed shape and are subjected to external pressure.They include liquids, gases, and plasmas.

3. What is fluid dynamics or what is fluid flow meaning?

Fluid flow includes the fluid motion due to some unbalanced force. Until external unbalanced forces are applied to the motion of the fluid, the fluid will continue its motion. The mechanics that deal with the study of fluid flow properties is known as fluid dynamics.

4. What is fluid statics?

The study of fluid at rest and fluid in equilibrium state is known as hydrostatics or fluid statics.

5. What is the classification of fluids?

Based on their properties, they are different types of fluid. They are listed below