[metroschultz]

I believe the idea is similar to running water over a window screen into a bucket.
Put the screen over your bucket.
Run your garden hose at a slow rate for a few minutes and observe.
Most, if not all, of the water goes through the screen into the bucket.
Turn your hose on full and observe.
Most of the water, but not all, goes over the screen onto the ground.
Turn the bucket at an angle and the full power water stream will almost completely bypass the bucket, while the low power stream still goes through the screen into your bucket. The greater the angle the greater the amount of water bypassing the bucket.
One of the simpler laws of hydrodynamics. Fluid does not like to turn corners and at higher flow or pressure rate the effect is more pronounced. I forget the formulas.
Also one of the hydrodynamic laws that can be directly applied to air flow, since air is a fluid and the difference is viscosity.