Naturally the question is "what is the new, lower velocity?" The answer is that the wind velocity after deflection by the blade is reduced to a value equal to the apparent wind velocity approaching the leading edge of the blade minus the velocity of the blade moving forward as shown in the graphic, i.e. (A - V). For a blade velocity, V, of zero, i.e. when the rotor is not moving, this reduces to the original wind flow velocity, W, but the wind has turned a corner to flow at right angles to move parallel to the trailing edge. In this case plenty of force is seen by the blade from the wind turning this corner but the wind's kinetic energy remains intact and no energy is converted nor is any work done on the blade.

When the blade is moving at a high speed this vector difference between the apparent airflow velocity, A, and the blade velocity, V, diminishes and so the resulting velocity after deflection is reduced to a low value. It is never equal to zero but can become quite close to it and in such cases for all practical purposes the kinetic energy of the wind is almost all transferred to the blade.

The strangeness of all this and being able to say with such assurance that the airflow is this or that comes about because it is based on physical laws that relate to it, in this case, Newton's Law. Why must the world continue to be left in a mind haze about how aerodynamic forces are generated when deductive reasoning such as this from known science can be so readily made available?