Aerodynamics

Introduction 

Aerodynamics is a branch of dynamics that deals with the motion of air and other gaseous fluids and with the forces acting on bodies in motion relative to such fluids. We can simply define it as Aerodynamics is the study of objects (cars, airplanes, etc.) moving relative to a fluid, such as air.

Relevant Properties That Affect the Aerodynamics 

There are many factors that affect aerodynamic forces.

The Object

Geometry has a large effect on the aerodynamic forces generated by an object. Lift and drag depend linearly on the size of the object moving through the air. The cross-sectional shape of an object determines the form drag created by the pressure variation around the object.

Motion of the Air

Lift and drag are associated with the movement of the rocket through the air, so lift and drag depend on the velocity of the air. Lift and drag actually vary with the square of the relative velocity between the object and the air. The inclination of the object to the flow also affects the amount of lift and drag generated by a given shaped object. the skin friction.

Properties of the Air

Lift and drag depend directly on the mass of the flow going past the rocket. The drag also depends in a complex way on two other properties of the air: its viscosity and its compressibility. These factors affect the wave drag and skin friction which are described above.

Basics of Aerodynamics

There are three basic forces to be considered in aerodynamics: thrust, which moves an airplane forward; drag, which holds it back; and lift, which keeps it airborne. ... In obedience to Newton's third law of motion, which requires an equal and opposite reaction, the airplane is deflected upward.

Aerodynamics applications in Aeronautics.

The aerodynamic performance, such as the lift and drag, of a body is governed by the flow of air across its surface.  Applied aerodynamics seeks to understand and utilize the fundamental aspects of this fluid flow in the analysis, design, and integration of aerodynamic geometries.  The field of applied aerodynamics covers a broad range of applications, involving generally any object that experiences aerodynamic forces in fluid flow, though common applications include fixed-wing or rotary-wing aircraft, wind turbines and propellers, ground and marine vehicles, internal flows, avian and insect flight, and atmospheric flows.

Fluid mechanics and Aerodynamics

While aerodynamics is at the core of all aerospace engineering programs, the broader discipline of fluid mechanics, encompassing both aero- and hydrodynamics, covers a vast array of topics. The range and variety of fluid mechanics problems is both breath-taking and refreshing.

In physics and engineering, fluid dynamics is a subdiscipline of fluid mechanics that describes the flow of fluids—liquids and gases. It has several subdisciplines, including aerodynamics (the study of air and other gases in motion) and hydrodynamics (the study of liquids in motion).

 2-D wing theory

Name itself describe the whole principle of working of wings are in 2 dimensions. When a wing is used neglecting the width or thickness of it then it is in 2dimensions hence 2-D theory is applicable. But wings have some thickness, there for a mean is drawn in wings or aerofoil using that it is treated as 2 dimensional wings. For incompressible and non-viscous flows, the vane can be modelled by the vortex distribution along the midline.

Compressible Flow

In general, liquids and gases are states of matter in the same class as "liquid". Incompressible flow is mainly handled in the case of constant density. In addition, when the density change in the flow domain is negligible, the flow can be considered incompressible. This is always true for liquids because the density of a liquid decreases slightly with temperature and moderately with pressure over a wide range of operating conditions. Therefore, liquids are considered incompressible. In contrast, compressible flow is generally defined as "variable density flow". It therefore applies only to gases where they can be considered incompressible/compressible, depending on the operating conditions.

Factors of Aerodynamics

Aerodynamics Factors-

The Wing-

The aerofoil has six main parts.

1.              Leading Edge

2.              Trailing Edge

3.              Upper Camber

4.              Lower Camber

5.              Mean Camber Line

6.              Mean Cord Line

 

Principal of Aerodynamic

The four powers of flight are lift, weight, force and drag.  This force moves an object up and down and fast or slow.  How objects move through the air changes with each force.

What is weight?

Everything on earth has weight.  This force is caused by gravity pulling objects down.  In order to fly, something is needed to push the plane in the opposite direction of gravity. 

What is lift?

An elevator is a push that lets something go up.  This is the force that is against the weight.  Everything that flies must have a lift.  In order for an airplane to go upwards, it must have a lift in excess of its weight.  The hot air bubble is lifted because the hot air inside is lighter than the air around it.  Hot air rises and carries balloons with it. 

What is a drag?

Drag is a force that seeks to reduce something.  This makes it difficult to move an object.  It is harder to walk or run through water than through air.  Because water sucks more than air.  The size of an object also changes the amount of drag.  Most rounded surfaces have less drag than flat surfaces.  Narrow surfaces usually have less drag than wide surfaces.  The more air hits the surface, the more it drags.

What is thrust?

Thrust is the force that counteracts the drag.  A thrust is a push that pushes something forward.  In order for an aircraft to move forward, it must have more force than a drag.  Smaller aircraft can get thrust from the propeller. 

Aircraft and Aerodynamic

Aerodynamics is the way objects move through the air.  The laws of aerodynamics explain how an airplane can fly.  Anything that moves through the air is affected by aerodynamics, from flying a rocket to flying a kite.  Since they are surrounded by air, cars are also affected by aerodynamics.

How do airplane wings lift?

The shape of the aircraft's wings makes it possible for the aircraft to fly.  The wings have been shown solely to give a sense of proportion.  This shape allows air to flow faster in the upper part than in the lower part.  As a result, there is less air pressure on the wings.  This low pressure moves the wing and the plane attached to it.  Using a curve to affect air pressure is a trick used in many aircraft.  Helicopter rotor blades use curved shapes. 

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