bladeless wind turbines?

[Rdivine]

There's a company that's initiating a kickstarter campaign to start bladeless wind turbines.

http://www.vortexbladeless.com/home.php

https://www.technologyreview.com/s/537721/bladeless-wind-turbines-may-offer-more-form-than-function/

I've been trying to figure out how it works, and how the energy is harnessed. I'm using the concept of vorticity in my school project, so i need to figure out:

1. The shape of the structure

2. How vorticity induces oscillation

3. How the oscillating energy is harnessed.

If you understand how it works, please help me by leaving a comment!

 

And if all these starts out okay, it may be one of the coolest ways to harness wind energy.

[Scotius]

I bet it's supposed to work like these:

https://en.wikipedia.org/wiki/Rotor_ship

Yes, those pipes are sails, and they do work. Very interesting idea, but i don't know if those 'Flettners" will be able to compete with normal turbines. Boats still carry normal sails around for a good reason.

[AngelLestat]

I will not put my money on it.

They are lying in many aspects according to their numbers in the official page.

The swept area is what matter most, like you can see, in a wind turbine the tips of the blades seems tiny, but they move so fast that they convert almost half of all the energy generated. 

Normal wind turbines reach 40% of efficiency in a decent range of winds, this vortex pole only can work in few wind conditions if it wants to take advantage of resonance. 

They claim that it would be so cheap that you can make 3 for the price of one, but even if that is true, they will still harvest less energy (due kinetic conversion and swept area).
MIT critics are also accurate. I can not help you with vortex wind calculation, you need special fluid software for that because there is no way that you can make a decent estimation with a formula, but you can calculate how much wind area swept and what is the conversion kinetic efficiency, the kinetic to electricity efficiency, the range of winds that it works.. then you have a more approximate number.
Just take as granted their kinetic wind conversion efficiency.. and start from there, you will notice that even with their numbers, does not have sense.

About wind energy future, I bet on Kitegen, even if the kite area does not seems much, but the swept area is a lot, because they travel at 70m/s or more, and the wind speed at higher altitude is constant and stronger.. like you can see what matter most is wind speed in power generation, because increase with V³

http://kitegen.com/wp-content/uploads/2015/05/KGV-S.p.A.-Presentation-ENG-1.pdf
http://www.kitegen.com/pdf/dossierkitegenen.pdf

Google has their own wind airborne technology with Makani, but I like more the kitegen approach.

Edited April 16, 2016 by AngelLestat

[Steel]

1 hour ago, Scotius said:

I bet it's supposed to work like these:

https://en.wikipedia.org/wiki/Rotor_ship

Yes, those pipes are sails, and they do work. Very interesting idea, but i don't know if those 'Flettners" will be able to compete with normal turbines. Boats still carry normal sails around for a good reason.

Not quite, those work by rotating and generating force, these proposed "turbines" apparently work by vibrating due to wrong vortices and converting this motion into energy with a linear generator similar to in a wave generator.

[shynung]

I think I slightly understand the theory behind it, though feel free to correct me if need be.

Tall buildings like skyscrapers swing back-and-forth like an inverted pendulum when wind blows. It keeps itself standing by virtue of the materials used being sufficiently flexible to tolerate the oscillating motion, but it needs a way to stop itself from collapsing due to oscillation-induced structural fatigue.

Enter the Tuned Mass Damper.

Source: 

 

The idea is that the object with the larger mass will transfer its momentum to the object with the smaller mass, and then damping the smaller object's oscillation. The effect is shown on the animation above.

The idea, I think, is that, rather than damping the tuned mass oscillation and wasting it as heat, it can be harnessed as a source of energy. It happens so that there is a device that can convert oscillatory movements into electricity.

Meet the Linear Alternator.

This is a possible piston engine design powering a linear alternator. The permanent magnet is fixed to, and moves with, the piston, while the generator coil is fixed to the engine block walls. The piston starts in the far-right position, receiving a fuel-air mix which is promptly ignited. The expanding combustion gases push the piston to the left, compressing an inert gas in the gas spring chamber. When the piston reaches the far-left position, it exposes holes in the cylinder walls leading to the exhaust, venting pressure in the chamber, and enabling the gas spring chamber to push the piston back into the starting position, completing the cycle. While all this happens, the magnet oscillates inside the generator coils, due to the piston's movement. This generates AC electricity, the frequency and voltage of which are directly correlated to the frequency and travel of the piston movements, respectively.

So, putting all that together:

1. The structural design depicted in the website is a pillar which is thicker on the top section than on the bottom section. This makes it top heavy, and very prone to oscillating when blown by the wind.

2. The structure may be equipped with a tuned mass damper, which allows it to transfer the oscillation from the structure to a small, manageable moving part, from which it can easily capture the energy contained by the oscillation.

3. The 'damper' part of the tuned mass damper might as well be a linear alternator, which absorbs the oscillating motion of the tuned mass and generates electricity.

And that concludes my analysis of the working of this 'bladeless wind turbine' object. It suffices for me to say that the concept is indeed plausible.

Edited April 16, 2016 by shynung

[cantab]

Vibration is generally considered a bad thing in structures and mechanical systems. It's a bold move to try and make a wind turbine that deliberate vibrates, and that's being creditable about it.

[shynung]

1 minute ago, cantab said:

Vibration is generally considered a bad thing in structures and mechanical systems. It's a bold move to try and make a wind turbine that deliberate vibrates, and that's being creditable about it.

I agree, this kind of design screams madness from a civil engineering perspective. The question is, is it crazy enough to actually work?

[YNM]

What about their efficiency ? Does it work better than the usual turbine ? Is it safe ? Would the DOE do it ?

Also the quote really takes it away. Vorticity best way of transfering energy ? You've never fly in crosswinds right ? And he claims he's learning this off Tacoma Narrows disaster !

[HebaruSan]

4 hours ago, Scotius said:

I bet it's supposed to work like these:

https://en.wikipedia.org/wiki/Rotor_ship

Wow, that's a pretty short article to have 26 "[citation needed]"s. Are you sure this is legit?

[InsaneDruid]

Sure its legit, and you just need to follow the sources that ARE linked.

[Scotius]

Well, boats and even small ships were built with those rotating sail\mast thingies and they even sailed around. So yes - it's legit and it works. They are just not popular, and i'm not curious enogh to check why. But, reading previous posts i take my bet back. Shynung's post seems more on the money