Eddies That Reverse Their Whirling Motion
Incident and reflected eddies, and how a vortex trades power for diameter
This page studies water eddies that often turn their whirling motion backward, distinguishing incident eddies from reflected ones. Leonardo observes that an eddy sometimes grows in power while its diameter shrinks, and at other times weakens while widening. The first case occurs when the water pours out through the bottom: the deeper water in the vortex is faster because it bears a greater weight of water above it, and since the water thrusts downward more than upward, it constricts the vortex's hollow and bends it toward the outlet. Two eddy figures are drawn at the right, one a coiling funnel above and a hatched bank below.
On this page
Eddies that turn their motion backward
A heading introduces the study of water eddies that often reverse their whirling motion.
Incident versus reflected eddies
Leonardo distinguishes incident eddies from reflected ones and notes that an eddy sometimes grows in power while diminishing in diameter, and sometimes diminishes in power while growing in diameter.
Why a vortex narrows as it gains power
When the water pours out through the bottom, the deeper water in the eddy runs faster because a greater weight of water lies above it; thrusting downward more than upward, it constricts the vortex's hollow and bends it toward the water's exit from the pool.