Changes

<blockquote>Transition to turbulence begins when some flow instability(such as the instability analyzed in sections (Bkc) and (Bkd)) leads to some fairly large scale disturbance(s)or “eddies” in the flow field. As these disturbances gather energy from the mean flow, they begin to spawnsmaller disturbances or eddies which, in turn spawn even smaller eddies. This process ends because,eventually, the eddies reach a size for which viscous effects become important and the very small eddiesare damped out by viscosity. Eventually, the spectrum of spatial or temporal eddy sizes reaches a “fully developed” state in which energy is fed from the mean flow into large eddies and then continually cascades down to smaller and then smaller eddies eventually reaching a size at which viscosity becomes importantand damps out those small eddies. In this fully-developed state the disturbance energy for any one size ofeddy becomes relatively constant though it can, of course, continue to change with the flow conditions.</blockquote>