Stories tagged aerodynamics

Holy cow, this video has everything: feats of engineering, seemingly impossible flight, scientific explanations, and instructions on how to do it yourself!

It's unclear who is actually behind it, but someone at Sciencetoymaker.org has posted a video of an amazing paper glider that is so aerodynamically efficient, you can "surf" it on a wave of air generated with your hands. I can't put into words how cool this is. Check out the video, and hit up the main site for the .pdf of the template.

Sep
27
2008

Fluid flow separation: The fluid flow becomes detached from the surface of the object, and instead takes the forms of eddies and vortices.
Fluid flow separation: The fluid flow becomes detached from the surface of the object, and instead takes the forms of eddies and vortices.Courtesy jaganath

Fluid flow separation explained with mathematics in 1904

In 1904, Ludwig Prandtl, considered the father of modern aerodynamics, derived the exact mathematical conditions for flow separation to occur, but only in two dimensions for steady flows.

Unsteady fluid flow in three dimensions explained with mathematics in 2008

A century later, George Haller, a visiting professor in the Department of Mechanical Engineering at MIT led a group that explained the mathematics behind unsteady separation in two dimensions. This month, his team reports completing the theory by extending it to three dimensions. Papers on the experiments and theory are being published in the Sept. 25 issue of the Journal of Fluid Mechanics and in the September issue of Physics of Fluids, respectively. Haller's coauthors are Amit Surana, now at United Technologies; MIT student Oliver Grunberg; and Gustaaf Jacobs, now on the faculty at San Diego State University.

Fluid mechanics theorists are excited

The equation will forever change the face of advanced fluid dynamics and will have a profound impact on many industries, including the aerospace and automotive industries. This quote from Daily Tech Review shows that this breakthough has theorists in fluid mechanics excited;

The new work -- if it survives the extensive peer review that is to come -- will likely go down as the greatest scientific advance of the decade. The research has already survived a strenuous initial round of peer review.

Equally important, this month Thomas Peacock, the Atlantic Richfield Career Development Associate Professor and his colleagues report important experimental work verifying the theory.

"This is the tip of the iceberg, but we've shown that this theory works," Peacock said.

Fluid dynamics makes a difference

Understanding how surfaces effect how an object flows through a fluid (including air) can make big differences in maximizing performance. Did the new swimsuits make a difference in breaking world records in Olympic swimming competition? How about the surfaces of baseballs, golf balls, and tennis balls? The effects on miles per gallon for autos and airplanes can save millions (billions?) of dollars.

Source: MIT News

There has been much hype lately about the ethics of chromosomal testing during the Bejing Olympics. Rather than sending a man to compete as a woman (as the Germans did in the Berlin games),An ostrich going for the gold
An ostrich going for the goldCourtesy swh
they should have entered an ostrich or perhaps a rhino. Check out the link above to read about high performing animals that would give our athletes a run (or swim) for their money.

Dec
13
2007

A swarm of humans: The sky is full of human gliders in the flying-squirrel-like outfits. The winged suits are the newest trend in sky diving, giving jumpers the chance to glide at up to speeds of 140 miles per hour.
A swarm of humans: The sky is full of human gliders in the flying-squirrel-like outfits. The winged suits are the newest trend in sky diving, giving jumpers the chance to glide at up to speeds of 140 miles per hour.Courtesy Matt Hoover
Working on the museum floor the other day, one of the volunteers in my gallery was telling me all about human gliding. He’s big on aviation and had some interesting stuff to share on things he’s heard about and seen (but not actually done).

Unfortunately, I wasn’t able to take any notes at the time, but it got me curious enough to Google around and learn more about human gliding. It appears to be just the thing for the sky-diving veteran who’s looking for a bigger adrenaline buzz.

How does this work?

The wingsuit that human gliders wear essentially turns them into a parachute. The flaps between the wearer’s limbs create an airfoil that generates lift as they inflate with air. Gliders can then manipulate their bodies to control the direction and speed of their descent. Jumping from a moving aircraft like an airplane or helicopter also gives the human glider forward speed that translates into lift potential which slows down the fall rate of gliders and gives them a higher glide ratio.

Here’s an awesome YouTube video of a human glider in action. (Warning: The video itself is unobjectionable, but the comments posted to YouTube contain profanity and other strong language.)

Human gliders, when keeping their bodies parallel to the horizon, can reach speeds of 110 to 140 miles per hour. Many human gliders, however, find it a bigger challenge to see how slow they can glide while maintaining their aerodynamics, sort of, but not completely like, stunt pilots stalling out their engines when they’re doing tricks. Some human gliders have slowed themselves down to speeds as low as 25 miles per hour and have lived to talk about it. A more conventional slow speed, however, is about 60 miles per hour.

A closer look: From above, here's a closer view of what's involved with human gliding.
A closer look: From above, here's a closer view of what's involved with human gliding.Courtesy Matt Hoover
While it’s still a pretty new technology to be used in the sky diving realm with experiments going back about 10 or 15 years, man has been striving to glide through the air for ages.

In the modern era, between 1930 and 1961 there were 71 reported deaths of people attempting to glide or fly with wings attached to their bodies. There were also four successful flights in that same time.

And it appears that human gliding advancements aren’t going to hit the wall any time soon. Experiments are now underway in attaching jet burners to the shoes of human gliders, giving them more thrust and speed to play around with in the skies.

It should go without saying, but nevertheless, don’t try this at home kids, Jackass actors or any others who are easily tempted to display poor judgment. Human gliders are very experienced skydivers who have studied up on this type of aerodynamics.

That all said, is this something that you’d want to try? Share your thoughts here with other Science Buzz readers.

Here are some links if you’d like to learn more about human gliding.

Technovelgy.com

Lucky Aviation

Wikipedia

What every budding young physicist should know. From Popular Mechanics.