Vertical Axis Wind Turbine Aerodynamics and Design 

The possible approaches for VWAT simulation: 1. Cascade model+Leishman-Beddoes dynamic stall model. 2. Double Multiple Stream Tube model. 3. 2D Point vortex +Leishman-Beddoes dynamic stall model+free wake model. 4. Lift line model + +Leishman-Beddoes dynamic stall model+free wake model or vortex in cell method to deal with the complexity of wake. 5. Unsteady free wake Vortex Lattice Method (VLM) or Panel method. 6. CFD methods based on sliding mesh or overset mesh technique and URANS.

Can you make the video of the maths and theory of aerodynamic analysis of a VAWT

give us the math!!!! i love your work. it is verry inspiring

I'm a newbe - sent here by Dave Borlace of "Just Have A Think". Great content - thanks!!

Great Video!! I'm Currently in my final year at university and I'm working on developing the Double Multiple Stream Tube model (DMST) to analyse VAWT turbine performance. So, I'm voting for this for the next video!!! Would love to see your breakdown of it, seen as it's an extension of this video. Or even the single/multiple tube model.

These videos are gold dust. This is what RU-vid should be like as a norm. Authoritative and clear and no fear of the use of maths. Thanks a lot.

I am also interested in the detailed design video with all the math :-)

The scientific answer is unequivocally yes... I spent over ten years as a wind generator turbine and Axial Flux Alternator Design Engineer for the American Energy Research Laboratory. I designed, fabricated and studied many VAWT designs in dynamic environments. VAWTs are uniquely interesting but cannot compete with HAWTs in power generation on physical dimension characteristics. My data indicated the the swept area of a VAWT must be in excess of 4X that of a HAWT to produce a similar output energy production. That was when compared to the most efficient designs available. As an example: A VAWT will require a physical size of +360 sqft swept area (10' X 36') turbine to produce the production of a 10 foot diameter HAWT with 81 sqft of swept area. Both turbines will produce "realistically" approximately 500-1000 watts. Advertisers of wind turbines routinely indicate 2X - 3X more production based upon non-standard values. If you are interested... You can also "guess" the useful output of a generator by weight. Since most "motors" are fabricated using the same components and materials I use a simple rule of thumb. 26 pounds of generator = 742 watts. Once again.... Advertisers claim much much more due to various methods of non-standard calculations. How do I know this? 11 additional years employed as an Engineering Technician for a major motor manufacturing company testing many different motor and generator designs and producing valid data to design engineers producing more efficient products.

Surely the case for VAWTs should include their advantages at larger scale. This is the "elephants cannot jump" argument. As any structure is scaled up, stresses in that structure increase as the scale, so if you make something twice as big it has eight times the volume and eight times the mass, maybe eight times the cost, and gravitational bending stresses within the structure double. This is a problem for HAWTs, because this increase in stress applies to gravitational bending in the blade roots and this is a fatigue driver and hence a driver of cost of energy LCOE from HAWTs. VAWTS do not suffer this same cyclic fatigue stress and so were thought in the 1980s (when I did my PhD in VAWT aerodynamics) to be destined to replace HAWTs eventually when wind turbines reached large enough scale. (Aerodynamic stresses become less and less important with increased scale.) As it happens we are actually clever enough to make bigger things more expertly and so things including wind turbines do not increase in mass as the cube of linear dimension, but rather mass increases as scale to a power of about 2.2 to 2.6. Amusingly we might remember that body mass index (BMI) is calculated from mass/height^2, not height^3. The effect of this is that gravitational bending stresses do not increase as scale, but they still increase strongly. To combat these increases in stress we hear that more expensive materials (kevlar and carbon fibre) are increasingly used in modern turbines, perhaps to cope with this gravitational edgewise bending fatigue problem. Presumably there will come a time when it will be cost effective to switch to VAWTs?

Great video. Shows there are a lot of pitfalls in VAWTm design. I think they have great potential in urban areas without necessarily beating or matching HAWT efficiency...and I'd like to see the maths too

Halfway through the video I was saying to myself "control the blade angle like a helicopter!" I'm glad that was validated at the end haha.

Have you seen the Powerpod? Promising or puff? Thank you for the informative video!

Every company that has ever manufactured VAWT's has gone bankrupt. One problem is they require 600% more material than a HAWT per Watt produced which makes them heavier and more expensive too build and thus NOT-green and NON-economical.

Nicely done! One potential use for VAWTs, where there may be an improvement over utility-scale HAWTs, is for floating offshore wind. The lower center of gravity significantly reduces the size requirement for the floating platform, potentially reducing the cost of energy. Of course, fatigue is still an issue that must be addressed, and there are a few tricks up our sleeves that might help. The US DOE is funding a program (ATLANTIS) that it includes a VAWT design component.

I understood about 1 percent of this but was fascinated enough to stay to the end. Thank you for providing me with much needed rest time.

What do you think of Icewind turbines? I've been trying to figure out if any vertical design would work in the weak air pressure of Mars,

Great video !! I'm a retired mechanical engineer and I'm building my dream ranch totally off grid and as much recycled materials as posible. I've built a vawt at my off grid home to suppliment the solar system. I've tried several airfoil shapes and materials most of which have failed. I've studied that vawt are self governing and with our near constant wind here and gusts up to 80mph, that's a plus. At the moment I've settled on 55 gallon drums cut in half as I hope to make this easy and inexpensive to replicate for the Free seminars I plan to give this year. I live in the poorest county in the U.S. and want to give hope to those who have very little and build their self esteem and confidence. We also have outrageous electric costs !! I have a total of $30 invested and my smart drive washing machine alternator/ motor makes 27 volts and 10amps in a 15 mph breeze. All of the design work I owe to the University of U-Tube and thanks for you and everyone sharing your skills to help the world. Charlie

Great video, Rosie. One thing I’d be interested to see is your thoughts and calculations on the clustering of VAWTs which I have heard increase their efficiency (unlike HAWTs which are disturbed by nearby turbines).

Can you recommend a commercial DIY kit? I have wanted to play with one as a hobby for a long time.

- very informative video! I think the Voith Schneider propeller's active pitch control system would make a great system to be adapted for use on VAWTs with active pitch control. Both the direction and the amount of pitch are variable so it would allow efficient operation over a range of tip speed ratios. The system has been used for many years on tug boats and other work boats/ships. I would like your reaction to the VAWT of US Patent #9,494,136. All blades are interconnected forming a stiff structure.

Hi Rosie, one of the problems with wind turbines is the destruction of birds and bats. Are VAWTs any safer than HAWTs for flying animals?

Hi there! Please do make this more detailed video :-)

I would love to see a video detailing the basic mechanical needs and physics of a pitch controlled H-style VAWT. It would be interesting to see how complex it really needs to be. Loved the video!

I love that you add a math component to your video......

Maybe you have made this video already but, I would like to see a use case analysis for a vertical wind turbine. Like, say a single family home wanted to install one; how much would it cost and when would the return on investment be?

I did my fourth year engineering thesis on this back in 1975. I was limited by computing power.

"Just Have A Think" talked about putting VAWT's in the center margins of busy highways to capture the "waste energy" from passing cars. That would seem to fit the definition of a turbulent flow (opposing flow?) and might help with overall efficiency. The space is usually unused, and any power generated could be used to power roadway lights at night. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-gcSnwW5v3f8.html

I'd love to hear your thoughts on so-called "solid state" wind turbines or if those are just far too new and unproven to have much data/theory on them.

Could you put a giant vertical access wind turbine on a skyscraper to generate, say, half of its own power?

Great presentation! Nice to see someone not treating me like an idiot when explaining something. As I see it, the biggest ADVANTAGE of VAWT is having the "guts" at ground level. The biggest DISADVANTAGE of the Darius-style is that they're not self-starting - but that can be fixed by having a Savonius-style starter turbine.

You talked about the drag on VAWT when the blades spin around and essentially move back into the wind but wouldn't the exact same principle apply to HAWT? HAWT's have aerodynamically designed blades to counter this but then couldn't the Horizontal type apply the same? Also from an aesthetic viewpoint (in urban areas) personally I feel VAWT turbines have the edge.

Give us the math! Also, it would be great to talk about what makes an efficient generator, especially for slower speeds (e.g. low speed wind recovery with vertical axis turbines).

efficiency only matters in relation to cost, no? it's all about that $/kwh

Can we please get the in depth video on VAWT design? Great video but I was expecting much more detail

Hawt vs. VAwt - from the computer industry, the idea of TCO (Total Cost of Ownership). Since with a VAWT, you place most of the mechanical (and all of the complex mechanicals) at the bottom, much reduced need to climb a 100m tower with it's concomitant risks. I think they're less likely to catch fire, too, saving engineer lives (no bailout systems on the power heads of HAWTs). As to blade-pitch control systems, there might be some ideas floating around in the sailing world, specifically wing-sail boats. I believe they are doing some good work in more passive control systems.

The whole way through I was thinking about changing the blade pitch, except using mechanical means. Probably not as good as doing electronically (as you could then adjust for wind speed as well as direction), but there are some relatively simple mechanisms that could be used at least to increase efficiency, even if it isn't quite maximised.

Floating VAWT have a good future as size can grow but with moving parts closer to ground level they are easier to maintain. For floating, the stability of the VAWT very important and does not require huge engineering and materials like HAWT structures!!

Hi Rosie! Thank you so much for all of your amazing videos! I started working for a company which supplies composite foams and balsas to LM Wind. Through that I was able to learn about and nerd out over wind turbines and specifically the blades. I'm currently in the Rocky Mountains, USA. I think that locally we could harvest a lot of ancient and modern ideas for green environmental control. For instance I have been really interested in Persian Qanats and ancient evaporative cooling techniques. I've been thinking about, for instance, having a qanat where each wind-catching tower has a VAWT atop it- the fluid dynamics of the qanat help cool interiors while the VAWTS atop a qanat tower might assist with pumping needs or maintenance of the qanat itself! Climate change is sadly irreversible and I neither an engineer nor a prepper but I am really interested in learning how to harness energy in nature to help us all survive in the future. Thank you Rosie for your awesome videos and inspiring content!

breaking up in extreme smile so many times ....I suspect someone is tickling her while she is trying to talk to us ................

Like many other viewers, I would love to see those math equations Rosie. Also it would be nice if you can tell us about any typical software that is used for those calculus. Thx!!

Are there any studies discussing the advantages of VAWT designs being easier on wildlife? Big vertical/curved blades would be easier to see and avoid, versus a HAWT with blades coming up or down at over 100mph that a bird won’t see? Thoughts?

Great content! When talking about pitch variability in VAWTs, a helicopter swash plate comes to mind. The greatest loss in efficiency is likely scale, as the area comparison of presented cross wind between VAWT and HAWT just doesn't compare.

Oh- just a suggestion, and you have probably already heard it: but as you grow your channel, the first upgrade I would suggest would be a microphone or three, and maybe a sound panel or two to take you of the well you are speaking from. I think the sound of a podcast matters more than even the video quality. Shoot- most cell phones can do video better than any RU-vid video just a few years ago. But good sound is harder and more important. Consider it the Podcast equivalent of Grandma proofing new software- although in this case, I would be the source of Grandpa proofing it;-) That said, I appreciate your podcasts!

Ive recently moved to a windy off grid location and have been wondering about VAWTs to make use of that wind, it seemed so simple to build in that the wind direction doesn't matter but it turns out there's a lot more to it than just the wind direction and length of the blades! Thanks for breaking it down so succinctly!

It would be interesting to make a VAWT with the actuated vanes. Make them out of composite. Put a steel-geared hobby servo at the root of each one with a battery pack. I'll bet with a lithium ion cell or two, that servo could last a long time. Have four vanes in the H-configuration. The base has the generator and a shaft encoder. Maybe have a wind vane and anemometer wired up through the center of rotation to the top. Have the servos control the angle of attack as it spins around, changing for speed and wind direction. Could be fun for a remote camp or mobile off grid situation. Just set it up somewhere and it should start and steer itself. Another idea: figure out some kind of angle of attack "circle" and use some kind of machine learning algorithm that would vary the load and angle of attack profile to maximize power generation, and then have it memorize that "map" for different wind speeds.

This was interesting. More math and CFD would be great. Thanks.

I maintain that you are engaging in a kind of false equivalency here: that VAWTs can be made as efficient as HAWTs. In your analysis you neglect the effects of turbulence created by the wind passing over the central shaft (and in some cases turbulence from the upwind blade). The turbulence affects the downwind blade at precisely the point it would be most efficient. In the case of HAWTs, wake turbulence is generated by the blades, but the wind carries the turbulent air downwind before it can affect the subsequent blade. Likewise, turbulence caused by the support tower is downwind and has no effect. I believe it would be good if you explained why & how it is that VAWTs would never match the efficiency of HAWTs. That's not to suggest they are useless. Your discussion of the benefits in gusty or sporadic wind is helpful.

Can you start using the actual certified vertical axis turbine that does what it says it does. The hi-vawt 3000???

thanks for your efforts in wind energy, you are doing a good job, can you put more on Double Multiple Stream Tube with VAWT

Piezoelectric materials to harvest energy from stress forces (or send signals to modify shapes). Ah, more complexity.

The active blade pitch vertical wing could be achieved more simply on a flat wing with leading and/or trailing flaps / slats (similar to a jet's wing) rather than varying pitch on the whole wing. I think the wing could be made to fly at every point in its rotation by changing it from (relative) concave to convex.

I enjoyed your video but your simple diagram of the Savonius windmill did not show the slight overlap of the blades at the centre. This gap provides the torque factor that makes the Savonius an ideal solution to pumping water as well as turning electrical generators through a gear system.

I think they could be on top of power poles in areas that get a good amount of wind.

please make a video about full analysis, and pitching control in VAWT, since only with pitching they can reach a huge efficiency !

Hi Rosie! I love your channel and what you’re doing with it. I accidentally put my comment as a reply to another comment, so it’s a bit buried now. I am interested in wind turbines for off grid applications for small cabins. I will likely install solar systems and the wind turbines will be supplemental to the PV panels. I have not done a formal wind study, but I looking into installing a weather monitoring station to start collecting data. I’ve live on the land for a year and that has shown me that we have gusty winds that are occasionally very strong. There is usually a slight breeze, but I would not classify the land as a high wind location. Thanks so much!! Tom

I live in north Texas with constant, powerful wind. I use VAWT exclusively, utilizing both Darrius as well as Savonius designs I have refined over the past 57 years. I am 74. My vawts have completely overcome flutter, stall, vibration, over-speeding problems as well as have zero electrical loading and unloading with wind speed and frequency changes, because one design utilizes 4 moving parts, while another utilizes 2 and ALL my birds compress air into an air grid for storage. Electricity is manufactured in my shop utilizing any of several air-driven engines of my own design. I have several air-driven appliances I have manufactured over the years. Edit: New Sub. I love physics!

HI Rosie, greetings from Colombia. I wonder what is your opinion on ART wind turbines? Is ot worth the trouble? Thanks for your job in communicating this extraordinary world of wind power!

how do animals interact with vertical wind turbines? I many birds die from collision with horizontal turbines.

Hi Rosie! Thank you so much for sharing your well-articulated and super informative videos here on RU-vid. You are a truly inspiring educator. I am a senior wind turbine control systems engineer in the U.S. and have recently been designing the control system and algorithms for a ~100kW H-type VAWT. The turbine has three straight fixed blades, all aluminum. There is no blade pitch mechanism. The lead turbine engineer wants to regulate power in high wind (region 3) via stall regulation by truncating rotor speed past a certain wind speed, thus stalling the blades to prevent increasing torque with increasing wind speed. However, this strategy will generate turbulent flow and potentially damaging vibrations that will lead to early fatigue of the blades and arm connections, as you so eloquently explain in your videos. It is also dicey trying to stall regulate in this fashion because the generator and electronic power converter equipment is required to have sufficient overdesign to handle the surge torque needed to decelerate the rotor in gusty wind in order to keep the rotor in stall. Any slop in the RPM regulation can cause a runaway condition whereby the rotor overspeeds to the point aerodynamic torque exceeds the electrical torque capability of the system, thus the rotor suddenly becomes impossible to decelerate without emergency brakes. The reliance on generator torque to stall the rotor also makes for poor power quality due to electrical torque fluctuations and surges. I have been trying to encourage the design team to consider a future blade pitching approach to simultaneously reduce stall-induced vibrations while also making speed regulation safer and more robust. I'm also concerned with their choice to use aluminum blades, as they will fail sooner, making for a poor quality product and disappointed investors. What are your thoughts? Are you available for consulting? Our company is based in Northern California and our current design prototype is located in the Texas panhandle and is nearly finished. We are commencing initial tests next week.

Can we apply this to a blackbird type of vehicle preferably to a catamaran? I imagine there are forces on the pole that supports the blades that can be harvested for movement.

I looked into getting a residentially vertical axis windmill and was disappointed that there were so few providers and that I was told to not put it on the roof of my house due to vibrations. Now I understand why, thanks for that

Bring your voice-over mic into your talking-head shots instead of that inferior camera mic.

Hello Rosie, very nice video. I now have a good understanding to what to design for while developing my own VAWT. Can you make a video on which type of airfoil (a lot of different designs available out there) is suitable for developing a 3/4 blade Helical-VAWT. Thanks and Regards.

Очень интересно вас посмотреть спасибо ! Но вы не сказали про саму форму лопасти какой она должна быть ?

I think the helical turbines look pretty good, almost like some art installation. If I wanted one I'd probably choose one of those.

I have little knowledge of aerodynamics, but I was wondering why HAWTs don't have winglets. I'm sure the answer is "they don't really help" but I was wondering why.

Hi Rosie, I have just discovered your Channel from a referral from "Just Have a Think". You are very knowledgable in the area of aerodynamics (among many other things) and I am wondering if you might have time to explain the way some yachts are able to sail faster than the wind - I'm thinking of those America's Cup yachts sailing in Auckland earlier in the year. How do they sail at 70km/hr when the wind is 15? And what happens to the aerodynamics when they go so fast?

Run unloaded and chip in generator to regulate speed and smooth electric with super capacitor

mam, does these VAWT works in turbulrnt wind condition

To unload motor electronic disconnect wire and reconnect to govern use thermostat anemometer to check wind speed

i am exploring vawt as a solution to a specific challenge on my sailboat. Small, quiet, doesn't have to be efficient - just consistent.

I do think VAWT has its own niche and should not try to compete with HAWT in terms of efficiency. However, we do need to find a way to improve its efficiency as much as we can while still maintaining its advantage over HAWT (omnidirectionality, lower cut-in speed, simpler design, etc). As you have mention in the video, for a distributed, off grid, remote area, and site with lower average wind speed, VAWT is the better choice over HAWT. Finally, i loved your channel and i am glad it popped up in my recommendation algorithm ! Cheers from southeast asia !

Hi everybody, I am such a DIY guy and I've started to build more than one VAWT on my backyard. I live in a place with 6m/s medium wind speed / year. So I 've done the math very simplyfied. 1 complete turbine (with generator, charge controler, batteries, inverter, etc) with the cost of materials up to 1000 euros and a medium of 500wh production for only 12 hours/day and 3 years of lifetime will make me save around 3200 euros of energy cost this 3 years. Minus the total costs, it can save around 2000 euros for 3 years. If we combine 2 of them the savings will double, so I can save 4000 euros for 3 years. For only 3 years of lifetime It looks enough efficient for me! In this case I think the low efficiency doesn't matter to much. And don't forget the carbon footprint. Mabe I'm wrong, I'll build it anyway.

Super cool to see women in engineering. Unfortunately still not a common sight.

My take on the VAWTs is that they tend not to chew up a lot of real estate, so, might be more practical for off-grid applications, especially if you need to run multiple turbines due to relatively low efficiencies. I am not an engineer, but I tend to see things from an engineer's point of view. I would like to see a multiple turbine setup using the helical blade design. Another thing that wasn't addressed is the lowest windspeed for practical generation. I envision a hybrid setup with solar as the primary, and wind as the night time/cloudy day backup. Sorry, I have rambled. You gave me a lot to think about, thank you

Help; Question ; I have a short RV with solos and want VAWT for nights, overcast. 12v or 24v on a removable pole for travel. hope to works with low RMP to charge house batteries. a old cowboy80.

I'm only commenting to add engagement to the algorithm.

With a "yaw tail" (to adjust for wind direction) a variable angle of attack can be controlled with a cam.

Hi All, can we produce 750 watt of electricity with any wind power specification given 150sqm of landcoverage with 5m/s or less wind speed?

Hi Rosie, I'd be interested in you analysis of icewind.is/ turbines. Certainly the primary mandate here is reliability, but what are they sacrificing in efficiency? Also would love your explanation of how these are self-stalling in high winds, is that marketing hype, or is there a well understood effect being used here? And if so, how much do you think it sacrifices the efficiency? Brian

Inflatable blades to change airfoil at speed

I think we often get over fixated on efficiency - it makes the choices look binary when often it is more like something or nothing. It may be better to have something less efficient as opposed to nothing at all.. All homes having a small hawt with energy storage may have greater overall impact/potential for creating renewable energy than big commercial installations. In the end they are complimentary and what we need is to reduce fossil fuel usage asap.

Hi Rosie, Lately I have seen talks about placing funnels around the vawt. Would that, in you opinion, be a path to follow to increase the efficiency?

Math is the language of science & engineering. Almost impossible to design machines without applying some math modeling to get the optimal results. I also vote with the others requesting the math for VAWTs. (NOTE: I have been acquiring some components with which to attempt to build a small VAWT for our rural property in the mountains, so I "have some skin in the game", so to speak.)

I heard that another advantage VWAT is that they can be placed rather close to each other if you have a field with many machines. It can be an offshore field for example. Wind flows are not so much disturbed by VWAT compared to HWAT. do you think that is true ?

"Less efficient" alone doesn't say enough, or warrant a judgment of "inferior". More important is the long-term analysis of total cost (including maintenance) and total energy output over the life of the system. It's easily possible that a lower-efficiency system generates more energy for less cost over its lifetime.

An elegant cam could change the pitch of the blades. Align the cam with the prevailing direction of the wind with passive fluid dynamics by using the drag of a tail.

Scientist 1: vertical axis turbines are best! Scientist 2: no! Horizontal axis turbines are superior! Me: imma build a turbine on the Z axis 😎

I recently came across a pod like configuration (halcium powerpod) that channels wind up through a turbine that resembles an aircraft turbine. I believe it would fall into the Horizontal category by definition and I'd be interested in seeing how they overcome what looks to be a rather inefficient design. Especially as their claim of most powerful, safest is rather boastful and likely a play on the "safest" superlative. Perhaps this turbine is deserving of a third party engineering take from, say, Rosie the Engineer ;)

Super interesting. I have already subscribed. I do not know if you have dealt with this topic before. I rode you can't put horizontal axis turbines too close to each other because of turbulence. Does this problem also occur with vertical axis ones? For example, would it be possible to put several turbines next to each other on the roof of a house?

well, that is an analysis of a single mill, how about analysis of a farm, how close can they be to each other compared to horizontal axis. and stop calling them turbines, as engineer you should know those are not turbines because they are not compressing air.

I have a more gerneral question about windturbines. Why are there no ducted windturbines when they are more silent and efficent and why isnt there a impeller version of a ducted Turbine? Is this purly a structural problem?

Vawt haven't gone anywhere. They were suppose to get popular for residential and commercial settings and that didnt work at all.

I think the Wind turbine community could learn a fair bit from studying helicopter rotors, with regards to fatigue.

I've heard VWATs kill fewer birds than comparable HWATs. Is that true?

ok. bear with me. how about, with the pitch control one, instead of sensors we design it in a way the blades always face one direction. then we use that fish tail thing oh hawts to change that directio... aaand i made it too complex

4:28 blade speed should be in the opposite direction Vrel + blade speed = abs Wind speed Thanks for the great video

I have a VAWT of my boat and don't need the efficiency but need one that does not go ballistic in very high winds in the ocean. André

Nice! You're the real deal obviously. Tricky stuff, plain language, clear take home messages that even I get. Would love a more mathematical vid though it'd be mostly lost on me. Keep doing your thing.

Hi Rosie! Usually wind turbines mikes a lot of noise when used in a sail boat. Do you have any advise on which model (models) do less noise ? Thanks