Re: AAT:Questions

George Black (
Thu, 12 Oct 95 21:55:16 GMT

>>Hurrah, (and may I add) as a sports diver for a number of years -- one of
>>things that no-one has mentioned here is the thermocline.
>>The energy of the swimmer/wader/diver is compromised by the chill factor,
>>workload (working against the tides, wave action, etc)
>Well, actually it's like this, with some historical background:
>Until around 1920's when Prandtl started to get some good results
>the field of hydrodynamics was kind of schizoid. On the one hand
>we had the engineering and experimentalists working with data
>from experiments (except for some simple results from Bernoulli
>equation). The scientific part consisted of the Navier-Stokes
>equations which nobody could solve for any real life case and
>if they did solve them with some approximations they didn't fit
>the data.

To say that you have lost me at this point would be an understatment.
The Bernoulli theory I know because it used to drive an Artificial Horizon
that I used to watch in a bemused state while flying VFR.
Perhaps you are thinking of the Law regarding pressure inversly proportional
to depth?

As I remarked before, as a diver I wore a wetsuit. This is an 3/8 inch
expanded Neoprene garment that retains and insulates a small amount of water
around the diver.
This small amount of water is warmed by the divers body heat, but, in a days
diving with frequent entries into the water you can get pretty chilled.
It is the effect of the descent from the (slightly) warmer surface water into
and beyond the area of the 'thermocline' that I was making the point about.