text: BERNOULLI’S PRINCIPLE AND SUBSONIC 
  
  AIRFLOW 
  
  All of the external aerodynamic forces on a 
  surface are the result of air pressure or air fric- 
  tion. Friction effects are generally confined to 
  a thin layer of air in the immediate vicinity of 
  the surface and friction forces are not the pre- 
  dominating aerodynamic forces. Therefore, 