Different types of forces

There are different types of forces that act in different ways on structures such as bridges, chairs, buildings, in fact any structure. The main examples of forces are shown below. Study the diagram and text and then draw a diagram/ pictogram to represent each of these forces. 

A Static Load : A good example of this is a person seen on the left. He is holding a stack of books on his back but he is not moving. The force downwards is STATIC.
A Dynamic Load : A good example of a dynamic load is the person on the right. He is carrying a
weight of books but walking. The force is moving or DYNAMIC.

DYNAMIC LOAD (moving)                                     STATIC LOAD (standing still)

 

Internal Resistance : The person in the diagram is sat on the mono-bicycle and the air filled tyre is under great pressure. The air pressure inside it pushes back against his/her weight. 

INTERNAL RESISTANCE

Tension : The rope is in "tension" as the two people
pull on it. This stretching puts the rope in tension. 

TENSION

Compression : The weight lifter finds that his body
is compressed by the weights he is holding above
his head.

COMPRESSION

 

 Shear Force : A good example of shear force is
seen with a simple scissors. The two handles put
force in different directions on the pin that holds the
two parts together. The force applied to the pin is
called shear force.

                                                                                 SHEAR FORCE

 Torsion : The plastic ruler is twisted between both hands. The ruler is said to be in a state of torsion.
                                                              TORSION

Classifications of FluidTypes of Fluids, Fluids,

Source: Uzochukwu Mike
What are types of Fluids?
Of what types/classifications are fluids in science and engineering study? What do you think is the definition of fluid? Fluids can be defined as substances that flow or deform under the application of shear stress, and these include liquids and gases. They are part of engineering study in many tertiary institutions of the world.
Basically, in the study of science, fluids are divided into two broad groups. These divisions in this write-up are known as types of fluids which are Newtonian and non- Newtonian fluids. Newtonian
fluids are those fluids that obey Newton Law of viscosity. Non-Newtonian fluids are the opposite of
Newtonian fluid in the sense that they do not obey Newton Law of viscosity. Non Newtonian fluids in this text are sub-divided into time-independent, time-dependent and elasticoviscous or viscoelastic
fluids.
Newtonian Fluids
What are Newtonian fluids. Newtonian fluids as written in the introductory part of this text are those fluids that concur (agree) with the Newton Law of viscosity. Viscosity is the opposition to the flow of fluids and it is measured in force per unit area of the fluid. The generally accepted unit of viscosity is Newton per meter square (NM -2 ). This is known as the SI unit of viscosity which is the same with that of stress.
Mathematically, viscosity is expressed as Force per unit area or simply F ̸̸ A. Newton law of viscosity
states that the shear stress on a fluid element layer is directly proportional to the rate of shear strain. In Newtonian fluids, coefficient of viscosity does not change with the rate of deformation of the fluid.
Examples of Newtonian fluids are: water, kerosene and air.It is shown mathematically as: τ = ηγ; where τ = shear stress, η and γ are coefficient of viscosity and share strain respectively.
Non- Newtonian Fluids
What are Non-Newtonian fluids and their classifications?
Non-Newtonian fluids are those fluids that do not obey Newton’s Law. They are the opposite of Newtonian fluids. Examples of non-Newtonian fluids are colloids, emulsions, pastes, sols, gels, thick
slurry, latex-based paints, and Biological fluids. Note that non-Newtonian fluids are many but these are few examples given. Non-Newtonian fluids do not exhibit the property of Newtonian fluids where
shear stress is directly proportional to shear rate.
There are three broad classifications of non- Newtonian fluids. These three classifications are: time-independent, time-dependent and viscoelastic fluids. The viscoelastic fluids can also be called
elasticoviscous fluids. One should not be confused because some textbooks relating to fluids may only one of these two names. Notwithstanding the three broad classifications of non-Newtonian fluids, there are also some other divisions of the three.
Time-Independent Fluids
As the name sounds, time-independent fluids are those non-Newtonian fluids that do not depend on time. They are those fluids in which the shear rate at a given point is a function of stress at that point
only. Examples of time-independent fluids are Casson, Bingham, Dilatent and Pseudoplastic fluid.
The Bingham fluid as an exampleof time-independent fluid does not flow at all until the shear stress exceeds certain critical value called yield stress. In this fluid, the flow behaviors appear like that of Newtonian once the system begins to flow. There is an internal structure in this type of fluid which breaks down before flow of the fluid can start. Notable examples of Bingham fluids are tomato puree, wood pulp suspensions, butter, drilling mud and toothpaste. When equation is used to represent Bingham fluid, it is represented as: τ = τ y + ƞγ , where τ y is yield stress.
Casson fluids also require a critical shear stress to overcome before flow can occur in the system. The
type of flow in this type of time-independent fluid is non-Newtonian, non-linear and parabolic in shape.
Casson and Bingham fluids are called plastic fluids.
Dilatent and Pseudoplastic fluids exhibit different characters on their own. Dilatent fluid is also called
shear thickening fluid. Dilatant fluid becomes more viscous as the shear stress increases. The shear stress increases much more rapidly than the shear rate in this kind of fluid. Examples of dilatent fluids are slurry and highly concentrated suspensions, like, Poly Vinyl Chloride. Pseudoplastic fluid is opposite to Dilatent fluid because the share rate increases much more rapidly than the shear stress.
It is known as shear thinning fluid. As the shear stress increases, pseudoplastic fluid becomes less viscous.
Time-Dependent Fluids
Time-dependent fluids are fluids whose shear rate is a function of shear stress and time. In this type of non-Newtonian fluid, the property of the fluid flow such as apparent viscosity changes with time. It is further classified into thixotropic and rheopectic fluid. In relation of thixotropic with rheopectic fluids, if the shear stress and shear strain relationship are observed with increasing shear rate, both sets of data do not coincide. This results to formation of hysteresis loop. In thixotropic and rheopectic fluids, at a given shear rate; there are two apparent viscosities depending on when the readings were
taken. The difference between the two is that thixotropic fluid becomes less viscous on application of stress while rheopectic fluid becomes more viscous on application of stress.
Elasticoviscous Fluids
Fluids that are predominantly viscous but show partial elastic recovery after deformation are termed elasticoviscous fluids. Examples of such fluids are multi-grade oils, polymer melts and liquid detergents. The term viscoelastic fluid is also used in place of elasticoviscous fluids as the former denotes solids with viscous properties while the later (elasticoviscous) denotes fluids that possess elastic property.
Conclusion
In summary, this write-up has dealt seriously on types of fluids based on science and engineering study. Fluids cannot be done without in our everyday life and this is one of the reasons that makes scientists to show more interesting in categorizing them and for more in-depth study of their flow. One of the basic types of food which people neglect is fluid. Do you know what that important fluid is? It is no other thing but the water we drink on our daily basis and I do not think you can do without it. Gasoline is another basic fluid used in automobiles and this is of great help to man. We cannot be able to power or motors on without this energy supplier. So, respect is to be given to fluids as they contribute to both technological and human development. Fluids were categorized broadly as Newtonian and Newtonian fluids. The non-Newtonian fluids were further divided into other classes and explained in sub-headings.
References
Fluid Mechanics by R.K Rajput;
Introduction to Polymer Technology by Dr. E. M. Katchy.

Classification of Automobiles

An automobile is a vehicle that is capable of propelling itself. Since 17th century, several attempts have been made to design and construct a practically operative automobile. Today, automobiles play crucial role in the social, economic and industrial growth of any country.
After the designing of Internal Combustion Engines, the Automobile industries has seen a tremendous growth.

Classification of Automobiles:
Automobiles can be classified into several types based on many criteria. A brief classification of automobiles is listed below:
1. Based on Purpose :
Passenger vehicles : These vehicles carry passengers. e.g: Buses, Cars, passenger trains.
Goods vehicles: These vehicles carry goods from one place to another place. e.g: Goods lorry, Goods carrier.
Special Purpose : These vehicles include Ambulance, Fire engines, Army Vehicles.
2. Based on Load Capacity: Light duty vehicle : Small motor vehicles. eg: Car, jeep, Scooter, motor cycle
Heavy duty vehicle: large and bulky motor vehicles. e.g: Bus, Truck, Tractor
3. Based on fuel used:
Petrol engine vehicles : Automobiles powered by petrol engine. e.g: scooters, cars, motorcycles.
Diesel engine vehicles : Automobiles powered by diesel engine. e.g: Trucks, Buses, Tractors.
Gas vehicles : Vehicles that use gas turbine as power source. e.g: Turbine powered cars.
Electric vehicles : Automobiles that use electricity as a power source. e.g: Electric cars, electric buses.
Steam Engine vehicles : Automobiles powered by steam engine. e.g: Steamboat, steam locomotive,
steam wagon.
4. Based on Drive of the vehicles:
Left Hand drive : Steering wheel fitted on left hand side.
Right Hand drive : Steering wheel fitted on right hand side.
Fluid drive : Vehicles employing torque converter, fluid fly wheel or hydramatic transmission.
5. Based on number of wheels and axles:
Two wheeler : motor cycles, scooters
Three wheeler : Tempo, auto-rickshaws
Four wheeler : car, Jeep, Bus, truck Six wheeler : Buses and trucks have six tires out of which four are carried on the rear wheels for additional reaction.
Six axle wheeler : Dodge(10 tire) vehicle
6. Based on type of transmission:
Automatic transmission vehicles: Automobiles that are capable of changing gear ratios automatically as they move. e.g: Automatic Transmission Cars.
Manual transmission vehicles: Automobiles whose gear ratios have to be changed manually. Semi-automatic transmission vehicles: Vehicles that facilitate manual gear changing with clutch
pedal.
7. Based on Suspension system used:
Convectional – Leaf Spring
Independent – Coil spring, Torsion bar,
Pneumatic.

Bernoulli’s Principle and Equation

During 17^th century, Daniel Bernoulli investigated the forces present in a moving fluid, derived an equation and named it as an Bernoulli’s Equation. Below image shows one of many forms of Bernoulli’s equation.
The Bernoulli equation gives an approximate equation that is valid only in inviscid regions of flow where net viscous forces are negligibly small compared to inertial, gravitational or pressure forces. Such regions occur outside of boundary layers and waves

The Bernoulli Equation can be considered to be a statement of the conservation of energy principle appropriate for flowing fluids. The qualitative behavior that is usually labeled with the term "Bernoulli effect" is the lowering of fluid pressure in regions where the flow velocity is increased. This lowering of pressure in a constriction of a flow path may seem counterintuitive, but seems less so when you consider pressure to be energy density. In the high velocity flow through the constriction, kinetic energy must increase at the expense of pressure energy.

Steady-state flow caveat: While the Bernoulli equation is stated in terms of universally valid ideas like conservation of energy and the ideas of pressure, kinetic energy and potential energy, its application in the above form is limited to cases of steady flow. For flow through a tube, such flow can be visualized as laminar flow, which is still an idealization, but if the flow is to a good approximation laminar, then the kinetic energy of flow at any point of the fluid can be modeled and calculated. The kinetic energy per unit volume term in the equation is the one which requires strict constraints for the Bernoulli equation to apply - it basically is the assumption that all the kinetic energy of the fluid is contributing directly to the forward flow process of the fluid. That should make it evident that the existence of turbulence or any chaotic fluid motion would involve some kinetic energy which is not contributing to the advancement of the fluid through the tube.
It should also be said that while conservation of energy always applies, this form of parsing out that energy certainly does not describe how that energy is distributed under transient conditions. A good visualization of the Bernoulli effect is the flow through a constriction, but that neat picture does not describe the fluid when you first turn on the flow.
Another approximation involved in the statement of the Bernoulli equation above is the neglect of losses from fluid friction. Idealized laminar flow through a pipe can be modeled by Poiseuille's law, which does include viscous losses resulting in a lowering of the pressure as you progress along the pipe. The statement of the Bernoulli equation above would lead to the expectation that the pressure would return to the value P₁ past the constriction since the radius returns to its original value. This is not the case because of the loss of some energy from the active flow process by friction into disordered molecular motion (thermal energy). More accurate modeling can be done by combining the Bernoulli equation with Poiseuille's law. A real example which might help visualize the process is the pressure monitoring of the flow through a constricted tube.
   

Despite its simplicity, Bernoulli’s Principle has proven to be a very powerful tool in fluid mechanics.
Care must be taken when applying the Bernoulli equation since it is an approximation that applies only to inviscid regions of flow. In general, frictional effects are always important very close to solid walls and directly downstream of bodies.
The motion of a particle and the path it follows are described by the velocity vector as a function of time and space coordinates and the initial position of the particle. When the flow is steady, all particles that pass through the same point follow the same path and the velocity vectors remain tangent to the path at every point.

 

 

 

 

 

During 17^th century, Daniel Bernoulli investigated the forces present in a moving fluid, derived an equation and named it as an Bernoulli’s Equation. Below image shows one of many forms of Bernoulli’s equation.

 

 

The Bernoulli equation gives an approximate equation that is valid only in inviscid regions of flow where net viscous forces are negligibly small compared to inertial, gravitational or pressure forces. Such regions occur outside of boundary layers and waves - See more at: http://www.me-mechanicalengineering.com/bernoullis-principle-and-equation/#sthash.2lIUkDNX.dpuf

Properties of Fluids

Understanding the properties of fluids is essential to analyse their behavior in working conditions. In this post I have written the fluid properties namely mass density, specific weight, specific volume, specific gravity, viscosity, vapor pressure, compressibility and surface tension.

Mass Density:
Mass Density (ρ ) is the property of a fluid is the mass per unit volume.

Specific Weight:
Specific Weight (w) of a fluid is the weight per unit volume.

Specific Volume:
Specific Volume (v) of a fluid is the volume of the fluid per unit mass.

Specific Gravity or Relative Density:
Specific Gravity (s) of a fluid is the ratio of the mass density of a fluid to the mass density of a standard fluid.

Viscosity:
Viscosity is property by virtue of which it offers resistance to the movement of one layer of fluid over the adjacent layer.

Vapor Pressure:
When a liquid is confined in a closed vessel, the ejected vapor molecules accumulated in the space between free liquid pressure and top of the vessel exert a partial pressure on the liquid surface. This pressure in liquid is known as vapor pressure.

Compressibility:
The normal compressive stress of any fluid element at rest is known as hydro static pressure which arises as a result of innumerable molecular collisions in the entire fluid. The degree of compressibility of a substance is characterized by bulk modulus of elasticity (K) .

Surface Tension:
Surface is a measure of fluid tendency to take a spherical shape, caused by mutual attraction of the liquid molecules.