Schauberger
This 'why' has been clarified by various of Nature's phenomena. Amongst others, the stationary trout that stands motionless in torrential alpine streams and flees upstream like lightning whenever danger threatens. Or spawning [The Energy Evolution - Harnessing Free Energy from Nature, The Life-Current in Air and Water]
which in turn the allotropic[1] primary materials for growth and development also reside. Reacting to bio-centrifugence, these basic substances are liberated through the cycloid-space-curve-motion of the Earth and under the influence of reactive cooling substances, consume (bind) the counter-weighing oxygen. Reactive differences in potential are created in this way which express themselves as reactive differences in temperature, which on their part, as all-penetrating inner outward<->inward, upward<->downward dynamic influences, intensify the physical (external) form of movement. This leads to a renewed intensification of the inner dynamic processes, which once again act to stimulate additional motion. Thus it is absolutely no wonder that the good old Earth eternally rotates about her peculiarly unique axis, because in this special axis (viz. the shimmering shaft in a water vortex) that something ascends, which enables stationary trout to stand motionless amidst torrential flows and to flee upstream like lightning. A phenomenon inexplicable in terms of mechanics, because the trout must not only overcome its own weight, but also that of the counter-flowing dense and heavy spring water. Indeed it can escape upstream all the more rapidly, the faster the cold specifically heavier water-masses, which whirl about their own axes in exactly the same way that the Earth rotates about hers, enter its jaws and flow out of its gills through a system of cycloid-space-curves. In this way the particular axis is formed in which that something returns to its ur-source, which becomes free through this special rotating motion and the frictional motion produced by it. In becoming free in this way, it then draws the motion-generating form - in this case the trout - in its wake, because this counter-flowing energy-form is the force that enables everything that crawls and flies on this manure-heap Earth to overcome its own weight. In other words, it is the 'levitational force', without which there would be no life, no movement, no growth and naturally no gravitation either. [The Energy Evolution - Harnessing Free Energy from Nature, New Forms of Motion and Energy]
Conversely, similar formative and levitative energies are created in front of the intake through primary processes of synthesis. These, for example, enable the trout to stand motionless in torrential streams, or to flee like lightning upstream when danger threatens. This is a phenomenon that cannot be explained mechanically, because the free-standing trout must not only over-come its own body-weight, but also the weight of the oncoming water. It overcomes this all the more easily, the more rapidly and torrentially the water containing these valuable threshold suspensions flows, which are reactivated [The Energy Evolution - Harnessing Free Energy from Nature, The Economy Founded on Reactively Produced Energy]
See Also