3 ms·

Please explain what you mean here in simple language. I don’t understand how you conclude that the upper flow must move faster and I don’t understand how it rel

• jjk166 5y ago
  To get a force acting upwards on the wing, there must be a downward reaction on the airstream. This downward force on the airstream bust change its direction. This change of direction is a rotation about the airfoil. Specifically a downwards rotation. The airstream moving above the centerline of this rotation is moving in the same direction, and thus will be accelerated faster. The airstream moving below the centerline of this rotation is moving in the opposite direction, and so will be decelerated to a slower speed. The center of this rotation happens to be along the camber line of the airfoil, so all the air above the camber line (ie over the top of the airfoil) must move faster, while all the air below the airfoil must move slower. The vortex is just the bulk rotational movement of the airflow. In fact, the airfoil can be replaced by anything that will generate the same vortex, like a rotating cylinder.