Whale of an idea for marine applications?

Discussion in 'Boat Design' started by JonathanCole, Mar 22, 2008.

  1. JonathanCole
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    JonathanCole imagineer

    Bumpy whale fins set to spark a revolution in aerodynamics

    Tubercle Technology - a revolution in aerodynamics [​IMG]
    March 21, 2008 It seems despite man's endless ingenuity and the incredible modeling power available to inventors through CAD systems, we keep looking to nature to find ever more effective ways of doing things. Millions of years of evolution's trial and error approach have resulted in some incredibly effective designs that are ready to be incorporated into human constructions if we can only identify, understand and replicate them. The random-looking bumps on the humpback whale's flippers have just inspired a breakthrough in aerodynamic design that seems likely to dramatically increase the efficiency and performance of wind turbines, fans, flippers and even wings and airfoils. WhalePower's tubercle technology seems like nothing less than a revolution in fluid dynamics.
    The humpback whale can weigh as much as 13 Hummer SUVs - and its unexpected levels of agility in the water have puzzled scientists for many years. Dr. Frank E. Fish (believe it or not) was browsing through a gift shop, when he noticed a group of small bumps on the leading edges of the fins of a humpback whale statue. Thinking it an error by the sculptor, he commented that the bumps seemed to be on the wrong side of the fin, starting an argument that would eventually lead him to discover an entirely new way of looking at the role of fins and wings in fluid dynamics.
    Current theory would state that the leading edge of a fin, fan or turbine blade should be absolutely straight and smooth for best effect - a 'fact' that has been taken for granted for decades. But the more Fish studied the odd leading-edge bumps, or Tubercles, the more it became apparent that evolution's work on the fin was far ahead of man's best efforts. Airfoils fitted with tubercle bumps showed much higher lift efficiency and greater stall resistance than identical airfoils without them. Turbines fitted with tubercles to the leading edges of each blade are able to produce more power at low fluid speeds, are quieter, and perform much better in turbulent fluid streams.

    It seems the bumps have the effect of channeling air into smaller areas of the blade, resulting in a higher wind speed through the channels and a number of rotating airflows on top of the blade which increase lift. Furthermore, the bumps eliminate the tendency of air to run down the length of the blade's edge and fly off at the tip, causing noise, instability and a loss of efficiency. In fact "bumps" is probably the wrong word as these are not small protrusions - on a utility scale (50 meter) blade for example, each tubercle would be about the size of a VW Beetle.
    After discovering the Tubercle effect, Fish worked with Phil Watts to invent and patent a new type of leading edge for airfoils and hydrofoils. WhalePower was then formed in collaboration with Stephen Dewar with a view to applying these designs to all types of turbines, pumps, compressors or fans.

    Wind power generation turbines stand to gain greatly from the discovery; because they can be used at a greater pitch angle with much less drag and much less tendency to stall, they allow turbines to continue generating power at wind speeds that are much too slow for traditionally shaped turbines to operate safely in. Importantly for the turbine market, tubercles can be retrofitted to the leading edge of conventional blades. Real world performance is proving very impressive, leading several major wind farm manufacturers to seek retrofit kits for their existing designs.
    The technology is in the early stages of commercialization by WhalePower, which is initially focusing mainly on the wind turbine market as a means of establishing itself. Currently Tubercle Technology is being licensed to manufacturers like Canada's Envira-North who will bring out the first big fans (24 feet in diameter) in April this year. Definitive R&D testing at the Wind Energy Institute of Canada (WEICan) is also about to take place and negotiations are in progress with a number of manufacturers who make everything from hovercraft fans to the tiny fans that keep laptops cool.
    While the company doesn't expect it to be easy to break into the market, WhalePower co-founder Stephen Dewar is confident that the commercial benefits of the technology will be so easily apparent that we'll soon see bumpy leading edges on a range of household and commercial goods.
    "If we've got what we think we've got, then the range of applications is staggering," said Dewar in an interview with The Star, "I'm honestly scared of making claims at this point. The results are so good that we know everybody who knows anything about aerodynamics will think we're salting the goldmine."

    We look forward to discovering how this nature-inspired technology stands up as a commercial product, and seeing its applications diversify as it matures.
  2. rwatson
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    rwatson Senior Member

    Thank you Mr Cole - a very, very interesting contribution. This sounds like an amazing bit of resarch

    I was a bit worried about ...
    "..... is confident that the commercial benefits of the technology will be so easily apparent that we'll soon see bumpy leading edges on a range of household and commercial goods."

    I was a bit worried that we needed to streamline our fridges and washing machines.

    But further research came up with
    ""We have an international patent going through everywhere," says Dewar. "It applies to all forms of turbines, compressors, pumps and fans."

    I started thinking of the energy savings of say a 20% efficiency could be achieved on commercial installations of all types.

    Who is going to the be the first with bumpy leading edge masts I wonder ?
  3. JonathanCole
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    JonathanCole imagineer

    I was thinking more along the line of the leading edge of props, or perhaps hydrofoils, although the application to sails might also be worthy of consideration.
  4. tom28571
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    tom28571 Senior Member

    Is this completely different from the fences that are used on the leading edges of some subsonic aircraft? If it is different, the tubercle people can not claim patent infringement if somone made multiple fences along a leading edge since these fences have been in the public domain for over 60 years.

    Just curious:)

    Can they sue the whales??
  5. RHough
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    RHough Retro Dude

    Help me out here ...

    What does a whale use flippers for? Propulsion or manoeuvring?

    I don't remember seeing anyone claim that a humpback flips its flippers to fly through the water in the way a bird flaps its wings.

    The propulsion comes from the tail and IIRC the tail is bump free.

    There is also the idea that evolution is adaptation, why don't we see leading edge bumps on other whales? Toothed whales like orca's don't have bumps on their flippers, other baline whales do.

    Do more efficient control surfaces benefit a hunter less than a grazer? Just how fast does a humpback have to turn to chase down elusive plankton? :)

    I don't see the connection between baline whale lumps and efficient foils. It makes for sense that the flipper shape (with lumps) is something that works for eating plankton with a sieve.

    What am I missing?
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  6. charmc
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    charmc Senior Member


    You're posing a good question. Fish himself noted four years ago that one possible reason no one had studied the bumpy fin/wing before might have been that it runs counter to just about all of the published data on fluid dynamics.


    I was thinking that the greater efficiency might help save energy on the baleen whales' long, slow migrations. But you're right; most of the energy in straight line swimming is from the smooth tail.

    Fish suggested the benefit of slower speeds and higher angles of attack before stalling might help in the tight manuevering the baleen whales do when circling a school of krill. It sounds reasonable, but I'm surely no expert. The article I cited above mentions low speed wind tunnel testing and measured results. Obviously, results in the real world need to correlate with the lab tests before the idea is proven, but their approach seems rational, and it will be interesting to follow the technology.
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  7. RHough
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    RHough Retro Dude

    Thanks for the link ... it begs more questions ...

    The first and most obvious question is who are they trying to kid? Testing a scale flipper optimized by evolution against one with the natural optimization removed? And the natural one wins? DUH

    How about comparing a Michael Selig optimized 22 inch foil with the lumps of nature? How hard is this? Oh, yes, tell Michael the Re range that the whale flipper operates in ...

    I'll take 5:1 on Selig.

    The second question is, why are US taxpayers funding this research? If a US Naval wind tunnel was used, the results should be public domain. Unless lumpy whale flippers are a national security risk ... (smirk).

    So wind tunnel data exists ... where? Why aren't the graphs and data splashed in bold print and highlighted? Maybe they don't look good when a valid comparision is made?

    Do lumps start sounding like snake oil to you yet?

    More from the link:
    Give me a break. Enhanced lift? Do whales travel with their flippers extended and swim/glide from water thermal to thermal?

    Why are submarines more efficient when submerged than when running on the surface? Why? NO wave making drag.

    Do whales swim upside down? No? Would 'enhanced lift' from the flippers drive them to the surface? Does swimming on the surface use energy at a greater rate than when submerged? Are lumpy whale flippers an evolutionary adaptation that requires the whale to use more energy and work harder to feed that need? Here is a hint ... the name for species that 'evolve' to be less efficient is "extinct".

    okay ... is there anything that smacks of truth in this press release pretending to be news?

    How about this:
    Hmmm ... ever seen a whale blow? If you can get past the stench (your dog has better breath) try to see this short event creating a 'wall of bubbles' or 'bubble net' ... tough isn't it?

    What might create a wall of bubbles and a bubble net?

    How about turbulence from great large lumps on your flippers?

    How hard is that to figure out?

    Here's how God or Evolution works ... the critters that stay around for a long time use as little energy as possible. Wasting energy is a bad deal, because it means you have to hunt more or find more **** to graze on. There can be more whales if each one needs less food, so whales evolve to need less food.

    Does spending more time on the surface 'making waves' save energy?
    Does having to overcome the increased lift from your flippers to stop making waves save energy?

    How about; Bubbles off my flippers let me catch more food for less energy.

    Use logic, remember what you learned in grade 9 biology.

    Now, why do whales have lumpy flippers?
  8. Frosty

    Frosty Previous Member

    Be carefull with evolotion here. Animals dont grow bits out of necessity.

    They grow bits from mutation that may improve a particular movement.

    If it does'nt improve then death will be the result, or quicker death. Meaning the live one breeds with the mutation, this will mutate again, and again and again.

    Mutation other than beauty has been totaly eradicated from the human race, we are no longer evoluting because we dont die from mutation any more, we no longer kill the runt.
  9. charmc
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    charmc Senior Member

    Good point about testing their foils vs those of some of the best foil designers.

    I don't know the answer about testing in a gov't facility. Gov't facilities can, sometimes, be rented for private purposes. Accounts of this research have been published for a while, at least 4 years. I haven't seen peer reviewed studies, but that could mean that they are in subscription only journals (small readership) or that they never published, which is not surprising if the primary purpose of the research is to develop a commercial product.

    As for your assertion that the krill encircling bubbles are a product of turbulence on the lumpy flippers, check the many accounts of the phenomenon. There appears to be no doubt that the bubbles are a product of controlled puffs of exhalation. Not the single breath you described, but a series of controlled puffs. Look at the photo; it's not a continuous flow of small bubbles, but a series of discreet groups of bubbles.

    I don't pretend to be a marine biologist, and I'm not not saying the lumps do everything Fish & Co. proclaim. Just that it's possible.

    Attached Files:

  10. kach22i
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    kach22i Architect

    Last year I started a thread with a similar tile/topic in the "Propulsion" forum.

    There are more links and articles in it if interested.



    EDIT, another application:

    Computer cooling fan:
  11. RHough
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    RHough Retro Dude

    Cool photo ... I was reaching with the air bubble idea.

    The point is that there is logic to evolution and successful mutation. Animals and machines that have the same needs tend to have similar solutions. The tails of whales (hey that rhymes) used for swimming are similar. Flippers on Orcas and Dolphins are similar. For a species to buck the trend and end up with lumpy flippers there must be a need that other species do not have. Find that need and there is the clue to the purpose of the mutation.

    After reading the Whale Power site and the press release/news report you posted the link to, it is interesting to hear what the 'inventor' has to say.

    On one hand the claim is that the lumpy flipper defies conventional aero theory ... then they go on to talk about spanwise flow leading to tip losses (we know that) and flow separation leading to stall and limiting angle of attack (and therfore lift)(we know that too).

    The resulting 'foil' does not have the same section at each point on the span (even when chord is constant) ... there is a large body of research (backed by empirical data) that shows changing the section like that does not produce more efficient (higher L/D) foils. The obvious comparison is the fabric covered wings on WWI airplanes. L/D is increased when the foil is fair in the spanwise direction ... sheeting the foil from the leading edge to 30-40% of chord pays with higher L/D. Partly because the wing has closer to the design foil section over the span and partly because skin area (and friction) is reduced.

    Look at the lumpy foil. The turbercles (or whatever) add area, so they must add drag. The foil cross section the tip of the lump morphs to a different section at the root of the lump ... just like the sag between ribs of a Spad the foil would do better if the best section in the morph was used and the foil was lump free in the spanwise direction.

    Now consider the spanwise flow limiting function of the turbecles. When you remove span wise flow you have nice neat 2D airfoil theory to work with. This is like a section that spans the wind tunnel from wall to wall. 2D theory gives results and predictions that don't work well in the world where foils don't have infinite span. When foils have tips the have tip losses. One way to reduce tip loss is to put an end plate on the wing tip. You can play with mid-span plates and quarter span plates and eighth span plates until you reach the point that you have a series of plates/fences that look much like the row of lumps.

    The turbecles may well limit spanwise flow and reduce tip loss, but this is nothing more that a different solution to a known problem. It is not whale magic.

    It is well known that turbulent boundary layers delay separation and stall. Are turbecles the best (lowest drag) solution? My guess is no. The boundary layer can be tripped into turbulent flow without changing the section. Spanwise flow control fences that don't change the section should work better too.

    An interesting test would be to take a Re optimized foil and see if flow control devices improve it. Add a trip wire and fences. Then add whale lumps. I would be very surprised to see that the lumpy foil performs better.

    How do you jump from a flexible manoeuvring flipper to a wing or turbine blade and assume what works on one (for reasons you don't know) will work on the other? The flipper does not have a constant AoA, it does not have a constant sweep angle, it flexes from root to tip while in use it is not much like a fan blade at all.

    It amazes me that someone can start with an assumption and then create tests to 'prove' it. They make two scale models one using the well known HBWF1 section (HumpBack Whale Flipper) complete with lumps and another using the same section with no lumps. They 'prove' to themselves that the lumps increase lift and reduce drag ... then claim an 8%? improvement for lumps? Then want you to believe that adding lumps to foils that were not designed for them like the HBWF1 was will see a similar increase. The logic is flawed.

    Ther must be a use for the flipper that is better with lumps, I cannot think it is drag reduction.
  12. charmc
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    charmc Senior Member

    Some great points there. Just a few quick thoughts:

    There are vast differences in design between efficient high speed wings and efficient STOL low stall speed wings.

    I agree that flexing flippers and rigid wings are vastly different.

    The type of literature published by companies promoting new technologies is intended to attract investors and/or customers. The technical term for that is sales literature. Responsible sales literature is fact-based, but its tone and purpose is more than presenting objective facts, it is designed to persuade, so it will emphasize benefits and minimize or exclude negative or neutral results.

    I did find a "real" scientific publication based on the research of Fish et al., in Physics of Fluids: http://scitation.aip.org/getabs/ser...00016000005000L39000001&idtype=cvips&gifs=yes

    Humpback whales appear to be the only one of the great whale species that perform the tight circle, bubble wall manuever to feed on krill, and they have relatively short, broad, and inflexible bodies compared to, say the blue, finback, sei, and minke whales. Something helps them perform tight manuevers; it may very well be the fins.

    I don't know if the lumpy blade fans and turbines will prove to be more efficient, but we'll all know once some are produced. Til then, it's all speculation.
  13. RHough
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    RHough Retro Dude

    There you go ... a logical explanation. Well done. :)

    It looks like the flippers have fairly high AR and it would be interesting to look at the relative speed during a turn between the inside tip and the outside tip.

    As you note STOL foil design and high speed foil design are different. I have never heard anyone claim that high lift devices to increase STOL performance are of benefit to foils that don't need to operate in that manner.

    The tight turn foil and wing planform requirements compared to high L/D foil and wing planform requirements is an interesting problem. Compare the evolution of soaring birds. Some have the high AR that you would expect and that work for sailplanes. Low AR wings should not be able to match those L/D numbers.

    Years ago, someone noticed that soaring land birds (hawks, buzzards, etc) should not be able to glide at high L/D ratios due to their low AR wings. Yet observation showed that high L/D gliding flight was common (at least in buzzards in Africa). These birds were also able to soar in tight circles close to the ground in small thermals. The answer they came up with was the fingerlike feathers at the wing tips acted as efficient winglets reducing the tip loss and enabling the low AR planform to both circle tightly and glide and high L/D. Model testing with a series of fingerlike winglets supported the theory and IIRC full scale experiments were made.

    I'm ready to buy that whale lumps help in their specific application just as the wingtip feathers work for theirs. I just find it hard to equate the needs of turbine and fan blades to transfer energy with the needs of a humpback whale to herd krill.

    I've never looked very closely at the differing needs (if any) for a turbine or propeller that provides airflow (thrust) from applied power and a turbine or propeller that provides power from airflow. Do the same sections work equally well if the turbine is driven or is driving a load? If the same sections work, then that would be a point in support of the flipper lumps, if the sections that make good wind turbine blades are not similar to sections that make good propellers or wings, it would make the lumps less likely to be of benefit.

    I'm not saying the case for lumps cannot be true, just that what I've seen so far smacks more of snake oil than science.
  14. charmc
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    charmc Senior Member

    The interesting thing about living things is their ability to make constant and minute changes. There was a documentary on PBS recently on various raptor birds. Its amazing to see how they are constantly moving individual feathers to adjust lift and propulsive power. Humpbacks are moving their pectoral fins constantly during manuevers, probably achieving similar effects. You're right, those long but flexible fins are a hell of a lot more complex than any rigid fin.

    Regarding airflow from power vs power from airflow designs; I'll just note that wind turbine blades tend to be quite long and slender vs aircraft props and hovercraft fan blades.

    Since the company is hoping to get a head start on any competition in bringing their fan blades to market, it's not surprising that they aren't releasing many details.

  15. RHough
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    RHough Retro Dude

    We will have to wait and see. :)

    I've looked at more than one patent that uses junk science to support the claims. I'm in the "If it looks like a duck and sounds like a duck ..." stage. I don't think I'm the most cynical person on the planet and there is nothing that I've read about the whale bumps that makes me sit up and say, "Wow, they may have something here."

    When they claim that retro-fitting bumps to existing blades improves performance all kinds of red flags come up. A blade would have to be poorly designed if disrupting the flow with whale bumps improves performance.

    That puts them in the same pew as the people that want to sell strips of golf ball dimples to reduce drag and increase the fuel mileage of your car. They demonstrate the effect and make a leap of faith that it dimples will work for everything. That product is patented also. Just think how much better turbine blades would be if you put both whale bumps and dimple tape on them ... ;)

    When something sounds too good to be true, it probably isn't true. How does the WhalePower marketing sound to you? They say they have field test results but they are 'confidential', they don't need to publish the data but:
    Read carefully ... they are developing the first full scale blades ... as in no full scale results yet ...

    One has to ask, what scale was the real world test? Is a 10-meter 30 kW turbine less than full scale?

    How about a teaser that can be verified when the full results make it into the sales pitch? X% average increase in power output in wind speed under Y ... if real numbers exist why do they make like this is a secret? They sound just like people that sell magnets for fuel lines and such. A slick site, a PC green energy tie-in and the too cute: "A Million Years Of Field Tests" slogan on the bottom of each page.

    When will WhalePower start selling blades? ... Never

    They are selling licenses to try to get the technology to work ... profit without liability. If you can't get bumps to work for you, it is not WhalePower's problem. Whales make it work, why can't you.

    Have I justified my skepticism yet?

    Let's wait and see. :cool:
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