Basic Aerodynamics

Introduction

  • Lift is created in an aeroplane through a difference in air pressures.
  • High pressure is generated below the wing and low pressure is generated above the wing.
    • The higher pressure wishes to rise up, and thus produces lift on the wing.
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  • This is caused by the plane wing's aerofoil shape
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  • Air tends to flow around an object so that it becomes streamlined
    • This is when air molecules tend to trail after their succeeding molecule, causing laminar flow.
  • A wing disrupts this flow and forces the air molecules to travel along the top and bottom, which have different lengths.
  • As the air wishes to remain streamlined, it aims to reach the receding edge at the same time.
  • This makes the airflow travel at different speeds, and by Bernoulli's Principle, this causes a pressure difference.
    • Bernoulli's Principle states that "An increase in fluid speed is matched by a decrease in fluid pressure."
  • In most wings, the upper surface has a longer length than the lower surface, and thus low pressure is generated above the wing.