Why air needs to flow faster (Bernoullis Principle)?
Imagine cars traveling quickly on a highway. Because they’re all going rather quickly, lots can pass a given checkpoint in a time interval (say 10 minutes). Now, imagine that the cars have to slow down for some reason (guard gates, for example, or a school loading or unloading zone). To get the same number of cars to pass a checkpoint in 10 minutes as on the highway, the traffic has to spread out sideways — everyone is moving more slowly, so to get 300 cars to pass your checkpoint in 10 minutes, you need many more lanes. The picture here — http://nymag.com/daily/intel/20070713yar… — somewhat illustrates this. The rail lines outside the loading yard can accommodate a lot of trains, but when they slow (to be loaded and unloaded, and for maintenance), they have to be spread out a lot. The flow of air is somewhat the same. It doesn’t “like” to be compressed — it exerts more pressure upon compression, and tend
