Whale tubercles for leading & trailing edge?
 

Found this and thought it may be an idea to help reduce turbulence on trailing edge on a vehicle. Website mostly talks about fan blades but if turbulence is reduced on a fan blade maybe the same can be done for a vehicle. :confused:

http://http://www.whalepower.com/drupal/

http://www.whalepower.com/drupal/fil...mpback_fin.jpg

http://www.whalepower.com/drupal/fil...blade_shop.jpg

Fixed the links, looks interesting!

A lot of great inventions were inspired by nature. In regards to aerodynamics though, a given design will not necessarily behave the same at 15 mph than 100 mph. This might work, but only tests will show.

ROFLMAO Fish...The guy's name is Fish!!

Dr Frank E. Fish...

Yeah, I thought that might be a joke but after reading further I guess not.

The working fluid is different as well. Somewhere in my fluid mechanics texts I have the method to calculate changes in fluid/speed/power/etc in order to do scale modeling. Buckingham Pi method IIRC.

I believe this is the inspiration for VGs.

Leading edge tubercles.

http://www.biomechanics.bio.uci.edu/...04biomech2.jpg

Are they just leading edge vortex generators?

yes

Sorry, nothing new I guess.

http://www.technologyreview.com/Energy/20379/page2/

http://www.technologyreview.com/file...blade_x600.jpg

It was new to me and I enjoyed reading about it. They are VG's but more so. Like advance VG's or improved design. Good stuff.

We have wind turbines in town where I live.

Hi All,

Very neet to apply this to wind turbine blades. But how does one apply it to cars?

I do not see a real obvious eco-modder applications. But it certainly would be a great thing for these big wings they put on ricer cars. They could generate more downforce for less drag.

One possible drag reduction application might be as some sort of aero device to improve drag in a side-wind situation.

Not sure if this is precisely a vortex generator. The protrusions would make a high and low pressure pattern across the span of the wing. The vortex might not be a vortex, but a planar back and forth oscillation that prevents the boundary layer from breaking up. As the protrusions do not stick up they do not create additional cross section area, like a VG does. Nor would they then cause a rotational flow perpendicular to the plane of the wing.

I can think of a lot of places where you could add these to the trailing edge of something on a car to improve drag CF.

- You could add a lip to the trailing edge of a hatch-back and it may work like/better then our standard VGs.
- You could add it to the trailing endge of the lips of the front bumper that some cars have
- You could add it to the trailing edge of side view mirrors

You might be able to put them in any of the places you might put normal VGs and it may have the same effect...

darn these blades are obsolete.

Nice thread... I think I included tubercles in my mega write up... but I'm with donee on this one

These are useful when you have a sharp leading edge on a plane parallel(ish) to flow... Like a turbine blade, whale fin etc. Ideally, one shouldn't have pointy bits, planar leading edges etc.

Reynolds number ;) Make them equivalent by changing the density property, then adjusting velocity to keep a constant ratio...
http://upload.wikimedia.org/math/9/6...7a29a45b92.png

Anyone know the average velocity of a whale with tubercles? Or better yet, the relative ocean velocity of a whale with tubercles?

"What do you mean? An English whale or an African whale?"


"Wha...oh...well...I don't know! AAIIEEE!" (Whoosh!)

tubercles and testoserone?
 

Fun read! Guess we'll all see if it goes in the marketplace.Ease of manufacture may be an issue.Thats some very sophisticated architecture. Pressure and velocity distribution could affect dynamic balance,and resonance ( flutter ) may affect structural integrity with high velocity applications, as there are so many local areas of impact,channeling,redistribution and discontinuities of aft-trailing -edge flow .Super-turbulence!Whales can articulate their flippers while turning,changing angle of attack at will as they pirouette in the water.The fluke of the whale is responsible for propulsion.I'd be more impressed if the tubercles were present in the fluke where the real power is laid down .Since whales communicate at extremely low frequency,could it be that the tubercles are "heard" by other would-be mating-age male whales and fertile in-season females,as tail-feathers are "seen" on the male peacock? Yep,I'm losing it alright!

Airtab
This company has supplied this RV manufacturers, seem to be doing well with Semi's and Vette's too.

Image
Or was this known already?
-Eric

A lot of people have been discussing Airtabs and a few have tested them on cars or pickups. Just type Airtab into the search box at the top of the page and you should get about 17 hits.

What if the whale is carrying coconuts?

You silly English-types! I faht in your genellal dilection!

Interesting idea. I'm thinking: canard configuration airplane with serrated edge main wing for stall resistance. General goal is low speed handling, agility and STOL characteristics. Need to do some more research though.

Are you thinking about RC or Full Scale?
 

I think one of my low-speed DIY RC SPAD planes might be a good test-bed for a saw-tooth LE.
http://i46.photobucket.com/albums/f1...SPA3D/654d.jpg

Since this type of coroplas wing has very little lift and can already fly at a pretty high AOA.
http://i46.photobucket.com/albums/f1...SPA3D/7409.jpg
It will be very easy to tell if there is any increase in hoover and handling.

I've just got to figure out the best way to implement the saw-tooth
and get some stick time.. :) Hope to have a plane ready by spring time..

Hi FX...,

I am not sure using the whale tubercles on a canard aircraft is a good idea. The idea of the canard aircraft is that the canard is designed so that it stalls before the main wing, as speed decreases. This way the angle of attack of the main wing never increase into the stall regime.

So, if you put tubercles on the canard wing, it does not stall. And the angle of attack of the main wing can be reached where it does stall, and the aircraft falls out of the sky.

Maybe you could put turbercles on the main wing, and then thin up the section of the canard. All would have to be tested very carefully.

fluke
 

Well-well! I saw a Pacific Life Insurance Co. tv "ad" on PBS television,showing their mascot whale breaching.The fluke was clearly visible in the video footage,and the flukes trailing edge was festooned with the tubercules.-------------- Also,in a PBS Boeing "ad",their new jetliner is shown with the new GE turbofan engines which use the serrated trailing edge.---------------- It's been explained that the jet is using it for acoustic attenuation.Perhaps do to the nature of a whale's low-frequency long-distance undersea communications,the tubercules reduce local dynamic "noise",aiding their ability to distinguish songs over background chatter.Don't know!---------------- As an aside,I've noticed old-time wood fireplace chimney caps with serrated edges under the rain cap.My thought was that perhaps the serrations might help to entrain errant cinders within the rising heat plume,allowing time for the embers to self-extinguish before settling onto combustible materials below.Don't know.

Finally found NASA paper on "tubercles"
 

After many months,I located the NASA paper I believed would shed some light on the whale tubercles.The paper is entitled "Investigation of Acoustic Effects of Leading-Edge Serrations on Airfoils," by Alan S.Hersh,Paul T.Soderman,and Richard E.Hayden.The paper appeared in JOURNAL OF AIRCRAFT,Vol.11,No.4,April,1974,pp.197-202,Copyright,1974.

The report is pretty technical.15 references are listed,going back to 1928.The research stems from observations of the aero-acoustic behavior of the owl wing,with it's leading-edge "comb",downy wingtop,and serrated trailing edge.

The research was conducted at NASA's low noise BBN acoustic windtunnel.

The crux of the research is that the "tubercles" eliminate "tones" created by periodic vortex shedding, by blasting the flow into turbulent flow and random wake turbulence.

Early roughening of wings produced increased drag,but Soderman was able to tune the serrations so as not to aggravate lift or drag while elliminating noise.

The test data is basically about frequency and sound pressure level.Of note,is the fact that above 10-degrees angle of attack,the comb makes no difference,as the wing is stalled at that point,and turbulence is random and without "tones".

Since "hearing" is so important to both whales and owls,the adaptations appear to be less about aerodynamic or hydrodynamic efficiency,and more about feeding efficiency.

The paper is a good read and I thank Paul for sending me a copy.

P.S. I believe PBS Television has free Pod-Casts of it's programs available at PBS.ORG. If you haven't seen "Raptor Force" on NOVA,you're missing out!

Notice that the whale tubercles are on the leading edges, with the trailing edge smooth. Nature had plenty of time to refine the tubercles, and chose the leading edge.

That said, the barred owl has serrated edges on its feathers, for silent flight. These are not as efficient for speed, but worth the sacrifice for stealth, especially at night.

Bumping this old thread, can we call this trickle down technology or just marketing?


https://www.ruppams.com/CatalogConte...VLS/HVLSRA.asp
https://www.ruppams.com/CatalogConte..._Tubercles.png

Looks like it can also cut bread for ya.

I saw an RC model with Vortex generators, does that count?

Opterra 2m Wing BNF Basic with AS3X

I put 1940 Buick tubercles on my rat bug in the late 70's.

http://ecomodder.com/forum/member-fr...-bahahaha2.jpg

I want to go all sci-fi movie and cut zombie heads off with that fan! :D

WTF?!?!

Stands for "whale trailing fins". :)

or just
 

*they might defend their claims with more science.
*it's a fixed-pitch fan,fixed angle of attack,non-tapered,non-twist blade design.
There shouldn't be any 'surprises'.
*I suspect that it's a sub-critical Reynolds number blade,all in laminar flow.
*blades don't stall at the tip.They stall over the aft-body portion of the blade on top.
*Whales and raptors actively morph their fins and wings as well as alter their entire body's angle-of-attack.The fan blades are 'static.'
* I think the acoustic argument is okay.Owls are virtually 'silent' fliers,using feather down and feather serrations to mitigate otherwise noise-generating vorticity as an evolutionary strategy.They can hear their prey,but their prey never hear them coming.

Thank you for commenting.

It's a cool looking fan, for those that look upward that is.

Not as much function as first impressions would give.

I have seen overhead fans installed on exterior porches to keep mosquitos away with moving air.

I imagine that these fans struggle with natures breezes and microclimate conditions of being next to a building and under an overhang.

Under these conditions a tubercle fan may actually provide an advantage, but again I would need to see some sort of testing information before drawing a strong opinion.

Didn't know where to dump this.

2010
Silent Helicopter Blades
https://www.trendhunter.com/trends/blue-edge
http://forums.pelicanparts.com/uploa...1505250689.jpg

Video in link above.

Similarly, I don't know where to dump this:

https://phys.org/news/2017-09-turbul...rs-plasma.html

Room temperature helium plasma jets modulated with sound waves.

https://3c1703fe8d.site.internapcdn....66f149239b.jpg

I reposted that article here:

Cool Science Story Of The Day [Continuing Thread]
https://phys.org/news/2017-09-turbul...rs-plasma.html

How about we start a thread called:

Aerodynamic Article of the Day (Continuing Thread)

It would be used for smaller items we don't want a dedicated thread on, and for things outside of traditional fluid bodies - perhaps.

Could include random images, like a breeze lifting up a persons hair or a skirt/kilt.................hurricane flipping cars...........

Random Aerodynamic Oddity of the Day.

Is that title above a better title?

How about this video of the wind pushing a dumpster on to a man in Russia?

Moscow storm catches a man by the dumpster.
https://www.liveleak.com/view?i=3c8_1496153911

Illustrates the power of the wind, maybe trash bins need to be aerodynamically shaped so they don't fly around?

I'm for it but I think it should be general enough to encompass for instance the Shawyer EM Drive:

scirp.org:Sobolev Spaces, Schwartz Spaces, and a Definition of the Electromagnetic and Gravitational Coupling

Is that a hoax?

Schwartz Spaces?

Is this subspace stuff anything like anti-gravity or implosions?

Schwartz space
https://en.wikipedia.org/wiki/Schwartz_space

Looks to be real, and I'm way out of my normal space. ;)

Not to my understanding. More to do with

Versor Algebra by Eric Dollard

Eric Dollard's interpretation of Tesla and Steinmetz is that the inductance and reluctance in poly-phase AC is an actual shifting forward and backward in time of the components of what we describe with sine-wave hand-waving.

It's all above my pay grade too. :)

Algebra is attempting to calculate your ex, right?

my ex- was calculating enough, thankyouverymuch.