Originally Posted by Lyman
Strictly speaking, it is the wing that is "flowing" (moving) not the air.
Physically it doesn't really matter whether you place yourself in the airplane and describe the airflow moving by, or you place yourself in air at rest and look at the airplane flying past you. If you want to discuss from the perspective of the "air's rest frame":
Dynamic pressure is just compression expressed as a result of motion. To deny there is compression of the airmass as the wing quickly enters is not correct, imho. Mass moves as a result of collision, Third Law? The Air Mass resists motion, First Law, viscosity.
Place yourself in the air molecule that meets the approaching wing at the 'stagnation point' close to the leading edge. When the wing has reached you, you will be moving at the same speed as the wing, and the pressure around you will have increased by the 'dynamic pressure'. Your acceleration from rest to the speed of the moving wing is not caused by 'collision' with the wing, but by the increasing pressure as the wing is approaching, because that pressure propagates forward in front of the wing (assuming the airplane is moving at subsonic speed). Sitting at the stagnation point of the moving wing, your air molecule has the choice of moving along either the lower or the upper surface. Whichever way your molecule goes, it will initially be 'pushed' along by the pressure reducing downstream from the stagnation point. Going along the lower surface, the pressure will reduce until at the wing trailing edge it has reached approximately the pressure of the surrounding air at rest, and the molecule will be moving rearward along the wing surface at about the same speed as the wing is moving forward, i.e. it will be approximately at rest relative to the surrounding air. If, OTOH, the molecule chooses to go over the top of a lift-producing wing, it's a different story. The pressure will reduce much more rapidly until it is well below the ambient pressure, by several times the dynamic pressure, and the molecule speed rearwards is much greater than that of the wing moving forward. However, past the point of minimum pressure the molecule decelerates because it is now moving against increasing pressure, until it finally reaches the trailing edge at about the same speed and pressure as the molecules that passed under the wing.
So, in summary, part of the lift is indeed due to the pressure on the lower surface being higher than the ambient pressure, but that contribution is small compared to the pressures acting on the upper surface being lower than the ambient pressure, commonly called 'suction'.
Bernoulli relates local pressure to local airspeed. Other than that, it does not explain why pressures and speeds change as they do. To explain that, you need viscosity and vorticity.