Aerodynamics is defined as the study of motion of air and its interaction with other objects. This is a field which combines fluid dynamics and gas dynamics. Aerodynamics helps in understanding the motion of air and the way it affects objects which is defined as flow field effects. Through aerodynamics, calculation of forces and moments acting on the objects can be found. The key forces which are focused on aerodynamics include the lift, drag, thrust and weight (Tucker 2016). On these key forces, lift and drag are considered aerodynamic since they result from air flow over the solid body. The major assumption when calculating the forces in aerodynamics is that the flow field is assumed to behave like a continuum. These are flows which are characterized by flow velocity, density, pressure and temperature (Houghton & Carpenter 2012). These properties are able to act as functions of position and time. In aerodynamics, these properties can be found directly or indirectly through experiments of the use of equations of conservation of mass, energy and momentum of air flows. In addition, the flow fields are also characterized by density, viscosity and flow velocity. These properties are able to define the relations between the object and air which flows over them. Ideal gas laws are used to define the different aerodynamics flows and types of aerodynamics.
There are several factors which are used to classify aerodynamic problems. The flow environment is one of the major properties which are used to classify aerodynamics. The major classification in this category includes internal and external aerodynamics. External aerodynamics is the study when the flow around the objects of different shapes (Ullrich, Gary & Dusenbury 2012). On the other hand, internal aerodynamics is the study of flow which passes through the solid objects. Flow speed is another key property which is used to classify aerodynamics. Subsonic aerodynamics happens when all the seed is less that sound speed and transonic if both speed below and above are present and approximately the same as sound speed. Supersonic aerodynamics is found when the flow speed is greater than speed of sound and hypersonic is when the speed is much greater than speed of sound. The third classification is done through the influence of viscosity. Inviscid aerodynamics is when very small viscous effects are felt and then considered negligible (Hawthorne 2017). In addition, viscous flow aerodynamics is when the viscosity cannot be neglected. Aerodynamics has applications in many fields such as vehicle design, sailing vessels, structural engineering, and aerospace among other field.
History of aerodynamic
The study dates since the 17th century although some key observations had been made earlier on in applications such as sailboats and windmills. The theory of resistance was once developed y Sir Isaac Newton in 1726 (Ferri 2009). The next development on aerodynamics was made by Daniel Bernoulli in 1738 when he came up with Hydrodynamica. This was able to describe the relationships between pressure, density and flow velocity for incompressible floe, which is known as Bernoulli’s principle today. This principle helps in calculation of aerodynamic lift in objects. Then Leonhard Euler came up with the Euler equations in 1757 which came in to define conditions for both compressible and incompressible flows. The equations were further extended in 1800s to in cooperate the effects of viscosity. This led to Navier-Stokes equations. These are some of the most simple equations of fluid flow but difficult to solve the flow around simple shapes. The four major aerodynamics forces of flight were identified in 1799 by Sir George Cayley (Von Karman 2010). The theories were later developed during flights and connected with circulation of fluid flow to lift. Moreover, researches continued and understanding about subsonic and low supersonic flow were done. The cold war led to the design of high performing aircraft, and this relied on different aerodynamic forces reactions. Supersonic and hypersonic aerodynamics ideas were later matured by 1960s.
Aerodynamic in the planes
In planes, aerodynamics is able to explain the way planes fly. It defines the different forces of drag, lift, weight and thrust. In this situation, the changes of the different forces and their interaction with air enhance the lifting of the plane and its flight (Leishman 2011). The interaction and changes of the forces in plane insure its moving up and down as well as faster or slower movement. In the plane also, the amount of each force and comparison with the opposing force determines the movement of the plane through air. The shape of the plane wings plays a critical role in lifting and making its fly. The planes winds are curved on top and flat on the bottom (Seddon & Newman 2008). The shape of the wing makes air flow over the top faster than on the bottom. Therefore air pressure is low on the tip and this leads to the lifting of the plane. The curved wings affect air pressure. The lifting force has to overcome the weight pressure of the plane. In addition, for the plane to overcome the drag force, they must generate the thrust force (Leishman 2009). The motor-driven propeller or jet engines provide thrust force required. The aerodynamic forces are able to control the plane during flight.
In cars, aerodynamics is able to affect the acceleration, top speed, fuel efficiency and handling. The major forces which are involved in car aerodynamics include the frontal pressure, rear vacuum and boundary layer (Hirschel 2014). These forces explain the interactions of the airflow with the cars body. Regardless of speed of car, energy is required to move through air. The frontal pressure results from the air attempting to block the car from moving forward. The air in front compresses the car and raises the air pressure in front (Bradford, Montomoli & D’Ammaro 2013). When the car is moving, the molecules of air move in the side of the car and lower the pressure than the molecules in the car.
The rear vacuum is caused by the “hole” which the vehicle moves while moving. The space immediately behind the car’s rear window is empty or a vacuum (Robert 2011). This causes the sucking of the car and therefore tending to pull it back to the opposite direction. This really creates a flow detachment since the molecules are unable to fill the space immediately.
The shell eco-car is one of the improved cars in terms of the aerodynamics to reduce the air frictional force. The shape of the car is done to ensure that the frontal friction is highly reduced. This shape of the car is one of the major merit of the car and ensures that the friction is reduced and therefore increasing the speed of the car (Passmore, Howell & Dominy 2017). In addition, the aerodynamic appendages are able to adjust and change shapes due to wind while the vehicles in motion are forbidden. In addition, the weight of the car is less and this ensures that the lift force is enhanced. The lift is perpendicular to the velocity of air and this ensures that less energy is consumed by the car. In addition, similarity of flow is achieved through the streamlined design of the car. This ensures that air flow is smooth and this enhanced the reduction of the pressure created during motion. More importantly, less energy is used when the car is moving. This is achieved through the combination of the different aerodynamic factors of the Shell Eco-car.
Nevertheless, the Shell Eco-car has some flaws. The reduction of weight reduces the stability of the car. The reduction of weight means that increase in speed will reduce the upper pressure and therefore making the car to be lifted up. This is dangerous and cause accidents. In addition, the car has low coefficient of drag (Happian-Smith 2013). This means that the car can move at high speed due to the low resistance it experiences. This may cause instability of the care due to the high speed. In addition, the low coefficient of drag gives lower energy which is needed since the air flow is smooth. This affects the effectiveness of the car operation. In addition, wind speed outside is able to change and this is able to affect the operation of the car. This is able to increase the frontal pressure due to the increased wind speed (Boeker & Van 2011). There are many molecules hitting the car since the speed of the wind increase. This pressure means that the car will require more energy to overcome the increased pressure. Although the drag is little, increased speed will need more energy to overcome the resistance.
The drag coefficient of car
The coefficient of drag in cars is a dimensionless number which is used to quantify aerodynamic drag on the car body when a fluid passes over the body. The drag has a direct relationship with the resistance which the car body is able to face when moving (New South Wales 2013). Low coefficient of drag in cars means that the car passes through the air molecules with low resistance. The coefficient of drag helps to shape cars in different ways in order to ensure that they can penetrate the fluid easily. Low coefficient of drag in cars helps to lower air resistances and enhance the performance of the cars. The coefficient of drag is influenced by the area of drag and therefore influences the aerodynamic efficiency of the cars (Sandler 2011). The coefficient of drag is derived from the friction between the fluid and the car surface. In addition, drag coefficient is able to change with velocity. Increased velocity means that many molecules are hitting the car body and affect the cars efficiency. In addition, the velocity of the cars is able to affect the coefficient of drag (Worms 2016). This is because there is usually increase in the number of air molecules hitting the care when the car speed increases.
Discussion how the aerodynamic help the new automobile to improve
First, improving the aerodynamics helps to improve the fuel efficiency for the vehicles. The latest automobile has a coefficient of drag equal to 0.19 (Huang, Gu, Feng & Zeng 2017). This coefficient means that little resistance is experienced when the car is in motion. In return, little energy is required to move the car and this helps to increase the fuel efficiency of the car. Reduced resistance means less energy is consumed by the car while moving and this has helped to transform the automobiles. Designs of bodies with less coefficient of drag have therefore helps to reduce the fuel consumption thus increasing efficiency. In addition, in the aim of increasing the fuel efficiency, the automobiles have been made lighter and smaller. The reduction of aerodynamic drag has been enhanced due to the need to have fuel economy in the industry. Reducing the downward force and lift ensures that the car is light and therefore can move with less energy (Pesich et al. 2017). All these are some of aerodynamic factors which are improving the new automobiles. In addition, in order to improve the Cd, automobile designers are making round edges of the frontal end of the cars. This helps to reduce the frontal pressure and ensures that the car can penetrate through the air molecules easily. This makes the automobiles more streamlined and therefore able to penetrate through the fluids easily.
In addition, lowering the automobile is another key dimension which designers are taking to improve the car efficiency and aerodynamics. The frontal effective area is widely reduced and in turn efficiency is increased. According to reports from Mercedes Benz, lowering the automobile has effect on the aerodynamic factors. It helps to a 3% improvement on drag (Rui 2017). This helps to increase the economy of the automobiles through less fuels consumption. In another way which the aerodynamics improve the automobiles is through the use of tabulator strips, vortex generators, diffusers and even short fairings (Passmore, Howell & Dominy 2017). These are able to ‘strip the airflow’ and therefore reducing the vortex transition between the roof and rear window. Large vortices trap the car and help to hold it back as it slips through air. Therefore small vortex increases overall efficiency of the aerodynamics of the automobile and therefore increasing efficiency. In conclusion, the aerodynamics has been enhanced to increase automobiles operations and efficiency. The shapes of the automobiles are as well changing to reduce the surface of air contact and reduce the frontal and side drags.
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