tip vortex thrust potential?

Like so... here's a large separation vortex on the windward side of the jib - the first pic is seen from above and leeward side, the sail is see-through, and the flow is on the windward side. The 2nd pic is how the telltails would fly, red ones on the windward side and blue on the lee side. This is rather an usual situation, when sailing upwind and a bit overpowered.

 

Yes, I want to eliminate all lift above the wing and increase the efficiency of the "smaller leading edge vortex" system to outweigh the drag induced.

 

What do you mean by "I want to eliminate all lift above the wing"? Lift is the component of force normal to the flow resulting from the integratrion of the pressure differences across the wing.

How well do you understand the basics of airfoil theory and wing theory for the simplier cases with attached flow near the leading edge and no leading edge vortex?

 

Great graphics! I assume the windward vorticity indicates a lower pressure and is on a aft facing surface despite being on the windward side. The vortex (or any suction) would, ideally, be on a surface perpendicular to the flow. 2 links at the top of this thread are examples of LEV on a somewhat forward facing surface. In the abstract, could such a system, dedicated to producing thrust be productive enough to outweigh the cost?
Not well enough.

 

looking at planes there are variations in between as well, half laminar half vortex, but what's good and bad

so idea is a flap in front of the vortices as Mikko showed on the jib above
sort of this fieseler storch flap, thought you ment forward extensions on a pure vortex delta wing

Crossplanes of Grid 5 (3.2 million cells) at four chordwise stations [19]: (a) x=400 mm; (b) x=500 mm; (c) x=600 mm and (d) x=700 mm.

here that vortex lift trapezium shape leading edge, yet -as i've read- think i like the sharp edge down;
clean and sharp cut, short attachment than cut again into the vortex, so say edge upside down, i may be mistaken tho

not having checked if open foam calculates lift in 3d i reread "the large drag of lift on the flat(?) lee side" any more links?

 

Lunatic,

I thought I was clear by explaining the process. I guess you are not getting it, I will try and be more clear:

YOUR IDEA WILL NOT WORK! WILL NOT, CAN NOT WORK. NO WAY IT CAN WORK.

You can not get more drive out of the wind than the energy the wind puts into it. It violates the laws of physics. Second law of thermodynamics: you can not get something for nothing. third law: you can not even break even.

the energy from the wind goes into creating the vortex, the vortex has a lot of internal drag (or friction that causes useless heating of the air), so the energy you get out of it for driving the boat has got to be much less than the force of the wind on the system. You can not use vortex lift to drive the boat into the wind.

 

Lunatic,

I think it may work.

Petros, stop yelling, relax.

Take few deep breathes.

Chill.

 

Thanks tom,

I am calm now. People yell when they think others are not listening. If they do not listen, they can not learn.

why do you think it will work? do you really undestand what the OP is trying to accomplish?

 

Thanks Petros.

I don't know if it'll work.

I was just trying to balance things out a bit.

I'm not sure what (s)he's up to.

How about we give him/her the benefit of the doubt and see what they come up with?

Slats work on airplanes...

I'd use 'em on hydrofoils if I could figure out how to make them adjustable.

Cheers!

 

Just trying to improve interesting rig I have sailed. Thought moving the position of vortex suction to a more forward-facing surface would reduce drag as indicated in the cited papers. It may be a misapplication of the cited papers, but illegal? The pressure graph in first paper shows more suction facing forward and since this is not an aircraft could even more suction be brought forward? Did not know the full costs of using vortices. There are limits to what is practical which I have probably exceeded, but no fundimental laws, I hope.

 

and forexample solar sails is another story

Edit: As a thought.. a windmill driving a prop boat straight upwind is within given laws

 

I have enough trouble keeping shadows off my solar panels while sailing, and trouble with vortices sailing upwind and posting on the internet. Maybe"ideally upwind" was a bad choice though sailing DUWFTTW has reached 2.1 X wind with a 17' prop bending lots of air. I am looking for incremental improvement from a lot less bending as an idea with little expectation of practical application. Have built models to study the formation and location of vortices but do not expect to see them on a boat soon, if ever.
For someone thinking outside the box from outside the box in need of guidance, I hesitate to give any. I have found many wind tunnel studies of sweptback planforms at less than 100MPH, closer to sailing speeds than I expected but I found in actual sailing a round LE spar with flat sail decidedly out performed a sharp edged wing, this was consistent on 2 different sweptback planforms. Hard to do comparisons with so few of these rigs sailing, and they do not compare well in theory.

 

Vortices seem oddly ubiquitous in a world of entropy. I should be studying them in a basic book or on a good site, not on a sail yet, though that is how my interest began, any suggestions?

 

here a populair site on specificly vortexlift and looking at the delta wing graph in it i remain curious
there is planty on the internet on vortices but "ups and downs" or "pro's and con's" i still have to refraise
maybe its better to start a vortex tread as props, water, wind and all things around us make them

 

starting with oars: http://www.concept2.com/oars/how-made-and-tested/vortex-edge still have to read in full, pics look like coanda effect

glad i didnt lose faith and started doubting the ones saying Marchaj made errors and with found with "Advantages and disadvantageso
of vortex lift" http://en.wikipedia.org/wiki/Vortex_lift

on another forum:
Typically delta wings have more surface area than swept wings of the same size, and lift generated is a simple matter of surface area, so delta wings indeed produce more lift than similarly sized swept- or straight-wing counterparts.

The primary benefit of a delta wing, though, is its trans-sonic and supersonic flight characteristics. As an aircraft approaches the sound barrier, shock waves build up along the nose of the aircraft, which then flow backwards to the wings. The shape of a delta wing keeps it clear of these shock waves, producing stable flight characteristics when near, at, and above the speed of sound.

There are other advantages: Delta wings are structurally stronger, have a higher maximum angle of attack (higher stall angle), and a greater interior volume for, say, fuel storage.

The main reason you don't see delta wings on commercial jets (except the supersonic Concorde) is that its shape gives it a large amount of induced drag (read: more money spent on gas getting the plane from A to B). The main reason you don't see tailless delta wings on fighter jets is that this wing shape tends to bleed off lots of energy in a turn, and good turn performance is very important for fighter jets.

all like Tom Speer said before, i just keep wondering how much angle, drag, speed to get that high lift
with falcon cfd giving drag (no lift) and showing suction areas on some deltas under variable wind and angles, takes patience but gives insight
not that my pc or falcon is perfect and can do all but geez.. wonder if i can put the clock back tomorrow to keep this trial running..