# Aerodynamics

## Aerodynamics

• Date Submitted: 03/08/2009 4:07 AM
• Category: Technology
• Words: 945
• Page: 4
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Does ‘Aerodynamics’ Mean?:
Aerodynamics ,one of the branches of dynamics, is about studying the motion of air, especially when it interacts with a moving object. We can also call aerodynamics as gas dynamics but the latter includes all gases. A flow field which means understanding the motion of air around an object makes the calculation of forces and moments acting on the object possible. Typical properties calculated for a flow field include velocity, pressure, density and temperature as a function of position and time. By defining a control volume around the flow field, equations for the conservation of mass, momentum, and energy can be defined and used to solve for the properties. The use of aerodynamics through mathematical analysis, empirical approximation and wind tunnel experimentation form the scientific basis for heavier-than-air flight.
Lots of ways are used to define aerodynamic problems. The first classification includes the flow environment. External aerodynamics is the study of flow around solid objects of different shapes. Evaluating the lift and drag on an airplane is an example for external aerodynamics. Internal aerodynamics is the study of flow through passages in solid objects.The airflow through a jet engine can be given as an example for internal aerodynamics.
The passage of an aircraft wing, revealed by colored smoke creates a vortex. Aerodynamics is accociated with many phenomena one of which is vortices.The difference in pressure between the upper and lower surface of the wing creates the vortex which is shown by the equations of aerodynamics.The higher pressure on the lower surface at the end of the wing tries to be the same with the low pressure side, creating rotation and the vortex.

A second classicification of the aerodynamic problems includes the ratio of the problem's characteristic flow speed to the speed of sound. A subsonic problem occurs when the speed of sound is faster than all the speeds in the problem. However a...