Swept Volume Theory

How true, my brain hurts.

By adapting a different FoR to eliminate air flow, wouldn't that mean tell tales would hang limp?

 

Ha! that means it's working, great!

Changing the FoR doesn't change the physics, just the way we think about it.
We know the tell tales stream and flutter. And that has to be caused by the the motion of the bubbles: filling in from leeward and being pushed away to windward.
The precise motion depends on how quickly the bubbles deform and move at different sail speeds, sail shapes and sail angles. It will take some wise thermodynamicists to delve into that. First of all we have to get them over the hump to stop thinking the answer lies in fluid dynamics!

 

That is what you choose a frame of reference for: to get convenient numbers. It makes no difference to the behavior of the physical bodies with respect to each other though. You are hung up on semantics which are irrelevant. In fact, since the Earth is moving at great speed with respect to the Universe, the air speed is also great. As always, it depends on your frame of reference.

 

Bubbles? Bubbles are a globule of one substance in another. I would like to understand where and how bubbles forms in your model. This is an explanation of bubbles:
Bubble Physics: Properties of Bubbles http://www1.phys.vt.edu/bubble/properties-of-bubbles.html

 

It's all explained in the subject of this thread, follow this link: Swept Volume Theory

 

I have just revisited the NASA site and see that they have done a big facelift, but are still presenting confusing data.
This diagram has the impossible discontinuity at 0% chord where, as you travel from the lower surface to the upper surface the pressure goes from increasing to 14.866 to increasing from 14.096

Now that's a discontinuity in anyone's language! There must be a mistake in the data source.

And the circular integral can only be evaluated if there is a function p = f(n) that can be integrated.
Since there isn't such a function, the integral cannot be evaluated, so it is a bit misleading in a "Beginners Guide".

 

This diagram represents the pressure distribution around an airfoil. You misunderstand it as ONE function with discontinuity, this is wrong imho. There are TWO functions, the lower surface (high pressure) and the upper surface (low pressure). Subtracting one integral of the other gives you the total amount of pressure which the foil experiences (hopefully it will be a negative value since you want to produce lift).

I'm not sure what is the purpose of your - sometime senseless - questions and ideas, they could probably mislead other readers and beginners.

 

All I have done is used the data in the chart to examine the pressure experienced by following the continuous path from the the trailing edge via the lower surface, the leading edge and the upper surface back to the trailing edge.
As it would be experienced by an observer using a pressure sensitive probe. Do the walk-around yourself.
As you approach the leading edge from below, the pressure increases from around 14.7 until it reaches 14.866 at the leading edge (at 0%chord).
Then, as we pass the leading edge, the pressure abruptly falls to 14.096.
That's a fall of the complete amount that the pressure changes around the surface!
That's a discontinuity!
Discontinuities do not exist in nature (this is not quantum physics, the only place where discontinuities definitely arise. This is apples-falling-from-trees Newtonian mechanics.)

 

There's nothing wrong with the data from NASA. There are no discontinuities.

If you can draw a curve (on old-fashioned paper & pencil) without lifting the pencil from the paper, then the curve is not discontinuous.

The curve you've drawn is not discontinuous. It appears to have discontinuous derivatives, but much of that is an exaggeration due to plotting against the x coordinate, instead of the arclength around the airfoil (and the rest just sloppy drawing on your part).

 

Do you believe the pressure falls the full amount, from the maximum, full-scale value of 14.866 psi to the minimum, full-scale value of 14.096 psi abruptly at the leading edge as shown on the graph?

 

You betcha it does. and these don't exist in nature either!

 

That's the second time you have used that phrase. What is "the arclength", could you sketch it out please?

 

It's the distance around the perimeter of the foil. ds = Sqrt (dx^2 + dy^2).

Using that instead of x will stretch out the curve so it won't look so steep to you.

 

Sure, why not?

 

I was referring to the curve you drew, not what you would get if you drew it more carefully.