Swept Volume Theory

Nobody is misquoting you. We're simply trying to think where you could have gotten that misconception.

 

And oh, yes, see Q1 in my theory, which I stand by:
"Q1: Why does the theory not include Bernoulli's Principle?
A: The theory does not mention Bernoulli's Principle because it does not apply to aerofoils. Here are two reasons, and while there may be more, disproving a theory only takes a single sound rebuttal.

1. Bernoulli's Principle applies to incompressible fluids. Bernoulli's Principle does not apply to air because, while air is a fluid, air is not an incompressible fluid.
2. Bernoulli's Principle derives the pressure gradient from a velocity gradient, but
   1. there is no explanation for a velocity gradient over an aerofoil and
   2. there is no experimental evidence of a velocity gradient."
      
      

 

What misconception?
Fossati P94:

 

You still believe all this? I'm afraid you're flunking out.

 

Does that sketch say anything about things always looking like that?

 

Without contradictory evidence (and its use in fluid mechanics texts is not evidence) you are "arguing by assertion".

• Charles' Law states PV=RT for a gas. That was proven in the 18th century.
• Present a theory for the creation of a velocity gradient.
• Present evidence of a velocity gradient.

How do you propose it looks then?

 

Now that the objections seem to have slowed to a trickle, can we turn our attention to using the theory to explain some of the mysteries of sail trim?
I take as my source "Illustrated Sail & Rig Tuning" Ivar Dedekam 1999, who, despite expounding the "path length" fallacy for the source of the suction:
" The shape of the sail forces the air flow on the leeward side to take a longer path than on the windward side. …" correctly explains:
"In effect a sailboat may be "sucked" through the water due to the low pressure on the leeward side. Conversely a slight increase in pressure will act on the windward side."
and ultimately presents many of the widely accepted and experimentally correct principles of sail trimming and rig tuning.

I am not contradicting these principles, I understand them to be correct, but I cannot find any explanation using classical mechanics for the reason why they are true.
Let's start with the first one, on P8, when discussing sail shape and draft position:
"Draft forward in rough conditions, draft aft in medium and flat sea."

Maybe we can find an explanation by considering the problem from the FoR of the undisturbed air.

 

Speculation on my part, I did read a long time ago that very efficient NACA profiles were easier to stall.

In steady conditions you can make use of the better lift/drag of draft aft.

When the mast is wobbling around the wind speed over the sail varies so you need to compromise to avoid flow separation.

 

Rough weather -> flattening sail -> draft moves forward

 

But aren't you just explaining one phenomenon with another ("better lift/drag of draft aft") that's equally unexplained?
Maybe I should have started with that, except that it's not offered in Dedekam's book.

Can I point out that "flow separation" a term primarily applied in fluid mechanics, and in the trickle flow of objections I think have established that fluid mechanics doesn't apply to air over sails.

 

I'm not sure this progresses the explanation.

Did you have any response to my #92 post?

 

You are so delusional!

Where have you given even a shred of evidence to back this up?

 

If you'd like to check, I have responded to all of your objections.
You appeared to withdraw from the discussion by not responding to my posts #92, #93 and #96.

 

Still wondering why fluiddynamics should NOT apply to air over sails..

 

OK, here's a recap of the argument:
Fluid mechanics relies on the Euler equations which rely on the density of the fluid being CONSTANT.
Air is compressible, its density is NOT CONSTANT. They do not apply to air.
The Bernoulli Principle applies to Incompressible fluids.

I can't prove a negative , it's up to the proponents to demonstrates the validity of their claim.