Sail Aerodynamics
 

MC wrote:

Your mistake is you you thinking you had posted anything except a series
of questions.

Oh? Let's see, did I post a bit of further explanation after Jax fell
short on tip vortex? It's in my "sent" file. Or did it go right over
your head?


... In fact, this is correct in so far as it shows that you
don't know what you are talking about -as I pointed out.

OK, in that case prove it. You explain 1- how tip vortex forms 2- your
calculations as to which represents a greater energy loss... flow
effects across the upper main from a frac jib, or combined tip vortex
from main + masthead jib.

If you can't explain it clearly, then you're bluffing. There is no third
alternative, is there?

DSK

Sail Aerodynamics
 

dougies, go back and re-read it until you understand about vertices (not
vortexes, but vortices).

"vertical pressure distribution"? dougies, dougies, dougies, the term is
"spanwise loading". Now, go back to study hall.

JAXAshby wrote:

dougie, the tip vortex comes about because the pressure on the windward
side of
the sail is greater than on the leeward side. The greater pressure tries
to
make it to the lower pressure. the air on the heavy side rolls over the
aft
edge of the sail in the easiest possible manner, which includes going up as
well as back. This makes for the vortex as the aft edge of the sail meets
the
forward edge.

A little slower, Jax... Navvie is taking notes...

You have got part of the explanation of tip vortex, so far so good. But if
what you
say is all there is, then why are there not a series of vortexes all along
the
trailing edge instead of just at the tip? Of course, when the flow is just
starting, that's true, but after flow is established there is just a vortex
at the
tip.

Another thing to account for is vertical pressure distribution.





having a main sail downwind of the jib does not cause the jib airflow to
stop
trying to go from high pressure to low pressure. The vortex generated
causes
turbulant air from the jib to screw up the airflow across the main. moving
the
top of the jib lower than top of the main just causes the jib vortex to hit
more of the main.

okay?

But that doesn't answer the earler question... the differential pressure
across the
main is going to interfere with (and suppress) the tip vortex from the jib.
Got it
so far? That means that energy lost through the jib head tip vortex will be
less.

Now, is that energy gain for a frac rig greater or less than the gain a
masthead
rig gets from not having the jib head tip vortex disrupting flow across the
main?

Folks, I think Jax *might* begin to actually grasp the question this time....
any
bets?

Fresh Breezes- Doug King

Sail Aerodynamics
 

dougies, what you are saying is bull****, pure and simple.

But that doesn't answer the earler question... the differential pressure
across the
main is going to interfere with (and suppress) the tip vortex from the jib.
Got it
so far? That means that energy lost through the jib head tip vortex will be
less.

Now, is that energy gain for a frac rig greater or less than the gain a
masthead
rig gets from not having the jib head tip vortex disrupting flow across the
main?

Folks, I think Jax *might* begin to actually grasp the question this time....
any
bets?

Fresh Breezes- Doug King

Sail Aerodynamics
 

Let's see, did I post a bit of further explanation after Jax fell
short on tip vortex? It's in my "sent" file. Or did it go right over
your head?


don't bother, dougies. what you posted in bull**** lifted from some writer who
didn't know any more about vortices that you do.

(do keep in mind, dougies, that *neither* you nor he knew that the plural of
vortex is votices)

Sail Aerodynamics
 

Let's see, did I post a bit of further explanation after Jax fell
short on tip vortex? It's in my "sent" file. Or did it go right over
your head?


JAXAshby wrote:
don't bother, dougies. what you posted in bull**** lifted from some writer who
didn't know any more about vortices that you do.

In other words, you don't know the answer and now you're running away.
But why are you running away so soon, Jax? Losing confidence in your
MENSA power?


(do keep in mind, dougies, that *neither* you nor he knew that the plural of
vortex is votices)

Both 'vortexes' and 'vortices' are listed as correct in my dictionary.
But when you don't really know anything about a subject, you quibble as
strongly as you can (which in this case, ain't very)

DSK

Sail Aerodynamics
 

dougies, I gave you the answer. read it again. And again, if you need to.
And again. And again.

Let's see, did I post a bit of further explanation after Jax fell
short on tip vortex? It's in my "sent" file. Or did it go right over
your head?


JAXAshby wrote:
don't bother, dougies. what you posted in bull**** lifted from some writer
who
didn't know any more about vortices that you do.

In other words, you don't know the answer and now you're running away.
But why are you running away so soon, Jax? Losing confidence in your
MENSA power?


(do keep in mind, dougies, that *neither* you nor he knew that the plural
of
vortex is votices)

Both 'vortexes' and 'vortices' are listed as correct in my dictionary.
But when you don't really know anything about a subject, you quibble as
strongly as you can (which in this case, ain't very)

DSK

Sail Aerodynamics
 

DSK wrote:



MC wrote:


Your mistake is you you thinking you had posted anything except a
series of questions.


Oh? Let's see, did I post a bit of further explanation after Jax fell
short on tip vortex? It's in my "sent" file. Or did it go right over
your head?


... In fact, this is correct in so far as it shows that you don't know
what you are talking about -as I pointed out.


OK, in that case prove it. You explain 1- how tip vortex forms 2- your
calculations as to which represents a greater energy loss... flow
effects across the upper main from a frac jib, or combined tip vortex
from main + masthead jib.

If you can't explain it clearly, then you're bluffing. There is no third
alternative, is there?


There is. That it would be a complete waste of my time trying to post
something you do not have the education to understand. Thus your post is
just another troll by you that is neither clever not amusing to reply
to. As for the answers to these questions #1 has already been posted by
Jax and others many times (but you didn't seem to understand it) and #2
has no answer unless you define the exact masthead rig and fractional
rig for comparison. If you wanted to enage your pitiful intellect for
just a second you might wonder why all the rig test show that optimal AC
genoa heads are near masthead. Pay me the money you owe me and I'll even
have student here run it in our advanced yacht sail design wind tunnel
facility for free for you.

Cheers

Sail Aerodynamics
 

JAXAshby wrote:

you asked a question, and yes or no were the correct answers.

as far as investment advice goes I can only repeat the advice of Will Rogers.
"Buy and when the stock goes up, sell. If it doesn't go up, don't buy".


Good lord he really walked into that one. I almsot head his nose squash!

LOL

Cheers

Sail Aerodynamics
 

DSK wrote:



(do keep in mind, dougies, that *neither* you nor he knew that the
plural of
vortex is votices)


Both 'vortexes' and 'vortices' are listed as correct in my dictionary.
But when you don't really know anything about a subject, you quibble as
strongly as you can (which in this case, ain't very)


Which just goes to show how those of little education can slaughter a
perfectly good language -in my opinion of course.

Cheers

Sail Aerodynamics
 

JAXAshby wrote:
dougies, I gave you the answer. read it again. And again, if you need to.
And again. And again.

Slow dow, Jax, you're backpeddling so fast you're almost out of sight

Wouldn't it be easier to be honest... just admit you don't have a clue.
You'll feel better and your therapist will be proud of you.

DSK