"Thomas Stewart" wrote:
Us sailors use tell-tales which tend to confirm Bernoulli to our own
eyes

If we(I) am wrong please tell me and give a visual example.

Ole Thom

If sail is set optimal according to the theory I use,
the tell-taless at the leech will stream nicely to astern.

Because that is what we(I) want,
direct as much wind to astern, so pushing yourself forward.

If your tell tales on the leech are not streaming to astern,
it means that the wind is not directed to astern,
and that you could do better.

I use the Coanda effect only to explain why the airflow
follows (or separates) the sail on the leeward side.

And yes, the air on leeward moves faster,
Not because the path is longer,
but because the air upwind from the sail is being sucked to the lower
pressure on the leeward, and pushed away from the higher pressure on the
windward part of the sail, what ofcourse will result in more airflow at
leeward, and thus a higher speed on leeward.
(This is called "circulation" in most theories)
so, tell-tales do not only confirm "Bernoulli", but also the theory I use.

I do not use the classic "newtonian" theory.
but again, what I use is on www.sailtheory.com/sail.html

Best regards,
Pim





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