What does the term "venturi effect" refer to in rotor streaming?

The term "venturi effect" refers to the acceleration of air flow through a constricted area. This phenomenon occurs because as air moves through a narrower passage, its speed increases while its pressure decreases, in accordance with Bernoulli's principle. In the context of rotor streaming, which involves the movement of air around and beneath rotor blades, the venturi effect is significant because it helps to understand how rotor blades can generate lift by effectively pulling air down and accelerating it through the rotor disk. This acceleration of air contributes to the overall dynamics of lift generation in helicopters and other rotorcraft, where the flow characteristics are crucial for flight performance.

Understanding the venturi effect is key to analyzing how rotor blades interact with the air to achieve desired flight characteristics, particularly in terms of handling and stability. In contrast, the other options do not accurately describe the venturi effect as it pertains to rotor streaming.