If you twirled such a whirly, the marbles would fly out of the spinning end. This is what happens to the air in the whirly. The faster you spin the whirly the faster the marbles and the air will flow through it. The wall of the whirly moves in a circle, to make the air inside the whirly move in a circle a centripetal force is needed. The whirly is open at the end so in the absence of centripetal force the air inside the whirly accelerates along the rotating tube.
Air flows through the rotating whirly.
Etc Bernoulli . Many people first guess that the air blowing across the end of the whirly reduces the pressure at the end of the whirly due to the Bernoulli effect and sucks air through the whirly. The simple experiment of blowing across the end of the whirly shows that this guess is incorrect. While the air does speed up as it flows over the end of the whirly, and while this speeding up is accompanied by a drop in pressure according to the Bernoulli effect, this drop in pressure plays a minor role in making the air flow through the tube. A quantitative investigation of the connection between sound frequency and the frequency of rotation.