DRAG Lift is the force due to the difference in the pressure between the lower and upper surfaces, multiplied by the planform area of the surface. The pressure difference between the upper and lower surfaces is adjusted by adjusting the surface geometry and attitude to the oncoming flow. Vary the Angle of Attack 2. In each case shown above, the flow moves more rapidly at some places than at others. In these regions of high velocity, the pressure is lower.
P is called the Static pressure.
Chordwise pressure distribution over an airfoil in low-speed flow Lift is related to freestream velocity by where is the lift coefficient, and S is the planform area of the wing. As the camber is increased, becomes more negative. Thus airfoil lift coefficient is . At the ends of the wings, the pressure difference between the upper and lower sides is lost, as the flow rolls up into a vortex. The overall lift is reduced, relative to the airfoil lift value predicted for a section of an infinite wing.