"Timothy Daniels" wrote:
> ...turbulence
> actually acts to scrub away the boundary layer of air (or
> other fluid) that surrounds the object to make closer contact
> between the object and the passing fluid.


Ignored examples of turbulence within a PC case
actually cooling a part without an increase in overall
air flow through the case is turbulence that is mechanically
produced by a fan. CPUs and Graphic Processing Units
have gotten hot enough in recent years to require a
fan to blow the air that is inside the case against the CPU's
and the GPU's heatsinks. No longer is the bulk flow across
the interior of the case enough to keep those parts cool.
But instead of drawing in more air per minute, the designers
increase the local air circulation to put more of that air into
contact with the heatsink. It is what some nutheads would
call "stale air" or "pre-heated air" that cools the CPU's and
GPU's heatsinks. It works by re-circulating the local air
against the heatsink until more of the heat has been extracted
than by a single pass of the air. This localized re-circulation
speed increase is also accompanied by increased turbulence.
Indeed, it is one form of turbulence, as there results no increase
in the bulk flow rate, just an increase in localized air movement,
as with all turbulence. That this increases the amount of calories
that the bulk air flow is able to remove per minute is a measure
of efficiency of turbulence is ignored and unseen by various
computer modders who would call themselves "designers".

*TimDaniels*