MASSIVE advances in aerodynamics

Aug 30, 2012
MASSIVE advances in aerodynamics
An image of the turbulent boundary layer. The velocity field of the turbulent boudary area. The turbulent flow exhibits a variety of arch- and cane-like vortex structures that evolve in time and space.

Engineers are closer to understanding, and therefore manipulating, invisible aerodynamic drag forces, that cause an estimated 50 per cent of transportation fuel to be lost before we can use it.

Director of Monash University's Laboratory for Turbulence Research in Aerospace and Combustion (LTRAC) Professor Julio Soria, said the technology to visualise these forces, which by causing drag or , , was now available. Understanding and controlling these forces could lead to significant financial and environmental savings.

"We are trying to understand the turbulent boundary layer - the region right next to objects' surfaces that causes drag on aeroplanes, ships, trains, trucks - all vehicles, as well as the resistance to flow of water, oil and gas in pipes" Professor Soria said. 

The LTRAC team is working on ways to manipulate this layer to control and reduce drag and increase .

"Based on Airbus estimates, even a 10 per cent reduction of this drag would result in a corresponding to about 25 per cent of the operational cost," Professor Soria said. 

The mechanics of turbulence of the boundary layer have remained a mystery because the structure of the boundary layer changes dramatically and unpredictably depending on the size of the object, its orientation and its speed. Further, it is almost impossible to effectively measure and analyse the conditions on a large object like the wing of an aircraft in motion.   

Despite the challenges, Professor Soria and his team are making progress by taking advantage of two super computer facilities - the Multi-modal Australian ScienceS Imaging and Visualisation Environment (MASSIVE) at Monash and the National in Canberra.

"We couldn't do these very large computations and visualisations without MASSIVE. To load and visualise this much data you need a supercomputer," Professor Soria said.

"Now we have better technology, we're seeing phenomena that we couldn't see before, and so didn't account for. As we delve deeper into the structure of the turbulent boundary layer, we find effects that we didn't even consider."

Professor Soria said the turbulent  flows the team is visualising are unpredictable, but not random. They can see patterns and can observe the lifespan of clearly identifiable coherent structures in what seems to the naked eye to be a random flow.

"Once we understand this, we can design surface control strategies that manipulate the to minimise drag which will result in more efficient vehicles, and less energy losses in the transport of liquids and gas in pipes. This will also reduce the amount of CO2 we produce, and the pain in our hip pockets."

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User comments : 18

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chardo137
1.5 / 5 (4) Aug 30, 2012
"Based on Airbus estimates, even a 10 per cent reduction of this drag would result in a fuel savings corresponding to about 25 per cent of the operational cost,"

I am not sure what the real numbers were, but I am pretty sure that this is not possible.
gwrede
1 / 5 (1) Aug 30, 2012
Flying 10mph slower, Southwest Airlines will save $42 million in fuel costs per year.
According to http://www.mpgforspeed.com/ at the bottom of the page.
GSwift7
4.1 / 5 (9) Aug 30, 2012
I am not sure what the real numbers were, but I am pretty sure that this is not possible.


It's because the relationship between drag and fuel use is parabolic. The first 10% of drag reduction gives a disproportional boost to fuel savings.

If you think about horsepower in cars, it might help you understand the concept. Due to drag, once you get over a certain speed, such as 50 or 70 MPH, it takes a larger and larger increase in engine horsepower to go another 10 MPH faster in the same car. That's one reason you see so many supercars that can do around 150, but so few that can do 200. Relatively few cars have the 600 horsepower needed for that kind of speed.

BTW, the graphic at the top of this article is really cool.
rkilburn81
3 / 5 (3) Aug 30, 2012
What if there was a way to calm the turbulent air in front of the vehicle by ionizing it or something so that you can pass through the air more smoothly?
Infinion
3.4 / 5 (8) Aug 31, 2012
"Despite the challenges, Professor Soria and his team are making progress by taking advantage of two super computer facilities - the Multi-modal Australian ScienceS Imaging and Visualisation Environment (MASSIVE) at Monash and the National Computational Infrastructure in Canberra."

ROFL, now I understand the title
MIBO
5 / 5 (1) Aug 31, 2012
if you think about it even in the simplest manner ( very oversimplified ), drag has several components with differing orders. different drag effects dominate at different speeds. At higher speeds induced drag will dominate.
for example the amount of air you move per second is proportional to your speed. The speed that you impart on that air is also proportional, but the kinetic energy imparted on that air is proportional to speed squared, so the overall induced drag has at least a third order component. 1.1 ^ 3 = 1.331, so a 10% drag reduction giving 25% savings does not seem at all unreasonable.
ab3a
not rated yet Aug 31, 2012
It's no secret that boundary layer control can yield huge dividends, not just with aircraft, but also with common every-day devices such as centrifugal pumps, valves, and many other things.

I have seen many vortex generators on aircraft wings that were determined more or less experimentally. It would be nice, however, if we had some concrete theoretical guidance on what boundary layer devices might be most effective. If it has to change at various speeds, it would also be nice to know how to change them.
antialias_physorg
5 / 5 (2) Aug 31, 2012
There's a reason why sharkskin (for example) is rough/textured. There's a reason why golfballs have dimples (much the same reason).

The idea to pattern wings has been around for a while, but for varying air densities and speeds the patterns need to be different. An active element is probably needed (like piezo-actuators under a smooth skin that can alter the texture according to senosory data just ahead of the actuator)
GSwift7
2.3 / 5 (3) Aug 31, 2012
An active element is probably needed


I think it's a bit early to make an assumption like that. The solutions might turn out to be very simple.

boundary layer control can yield huge dividends, not just with aircraft, but also with


This could also help us to understand birds and flying insects.

Additionally, if we get a better understanding of complex turbulence, that may allow us to create better simple approximations of turbulence for puposes such as weather forcasting, where the accuracy of our current models is limited greatly by uncertainty caused by turbulence and the time it takes to run detailed models of turbulence on supercomputers.

It will really be a MASSIVE breakthrough when we get to the point that we can treat turbulence as non-random in our models, though that point is still a long way off.
jakack
not rated yet Aug 31, 2012
What if there was a way to calm the turbulent air in front of the vehicle by ionizing it or something so that you can pass through the air more smoothly?


A good thought. I believe it is being done with plasma on military aircraft on the leading edges of wings.
http://www.dtic.m...DA446478

http://www.nd.edu...ma_2.pdf
Hengine
5 / 5 (1) Sep 04, 2012
I really really really hate the tiny thumbnails you use for the main article images. Like seriously, come on. WHY?
ScooterG
2 / 5 (4) Sep 06, 2012
I have an extreme dislike of false and misleading advertising, titles, and headlines. This article is a perfect example of low-class, manipulative, click-garnering, title-tweeking sensationalism.

Shame on the author, and shame on physorg for allowing it.
code red
not rated yet Sep 06, 2012
the drag is just above the sqaure of the speed, because air has to move faster over curved surfaces, at 500 mph say, parts of the air flow will be reaching the speeed of sound, pushing the drag factor up much higher, again it comes down to, faa, caa regulations what is allowed on an aircraft, safe to say if you have 100 percent control of the boundry layer, you can not only reduce the drag but recapture, the kinetic, displacement energy back again, but? its difficult, cause of the implications it almost seems a waste of time cause a lot of systems have to be safety tested its probaly possible to push a 500 mph aircraft, through mach 1..
islatas
not rated yet Sep 13, 2012
its difficult, cause of the implications it almost seems a waste of time cause a lot of systems have to be safety tested its probaly possible to push a 500 mph aircraft, through mach 1..


If there's a possibility of reducing fuel consumption for an entire fleet of aircraft by 25% there's almost no cost too high. Whatever the discoveries they could be applied to any object where drag is a concern. That's simply tremendous.
antialias_physorg
not rated yet Sep 13, 2012
I have an extreme dislike of false and misleading advertising, titles, and headlines. This article is a perfect example of low-class, manipulative, click-garnering, title-tweeking sensationalism.

Maybe the author just thought:
This is an article on science.
This will be read by people who are into science.
Therefore these people are beyond fart and dick jokes (and also have the ability to discern an acronym from INTERNET-TYPE-SHOUTING-BY-AOL-TEEN-FUCKWITS...in a headline)...all the while having a bit of fun with the title.

...just a thought.
code red
not rated yet Sep 13, 2012
i know a few tricks but can't afford the patents yet but i could save a lot o time an energy on this one not just the positive negative more advanced than that, could upset the military though plus a system for the engines but the complete air frame, needs re arranging.
code red
not rated yet Sep 13, 2012
the drag is just above the sqaure of the speed, because air has to move faster over curved surfaces, at 500 mph say, parts of the air flow will be reaching the speeed of sound, pushing the drag factor up much higher, again it comes down to,.. (FAA...CAA)..regulations what is allowed on an aircraft, safe to say if you have 100 percent control of the boundry layer, you can not only reduce the drag but recapture, the kinetic, displacement energy back again, but? its difficult, cause of the change, ground handling.. composites used it almost seems a waste of time, cause a lot of systems have to be safety tested, its probaly possible to push a 500 mph aircraft, through mach 1..it would be very interesting though..
AGTG
not rated yet Sep 27, 2012
i know a few tricks but can't afford the patents yet but i could save a lot o time an energy on this one not just the positive negative more advanced than that, could upset the military though plus a system for the engines but the complete air frame, needs re arranging.


I'd like to see that. We are working on several projects that could benefit by novel ideas. Give us a shout at
AGTGroup_MK [at] yahoo dot c o m

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