Featured Research

from universities, journals, and other organizations

Wind tunnel testing used to understand the unsteady side of aerodynamics

Date:
November 5, 2013
Source:
NASA
Summary:
Think about a time you've been a passenger in a car and stuck your hand out the window. As your speed increases, so do the vibrations in your hand. Trying to keep those fingers steady as the wind whips around them at 75 mph gets pretty tricky, right?

Wind tunnel testing of an SLS scale model at Ames Research Center.
Credit: NASA/ARC/Dominic Hart

Think about a time you've been a passenger in a car and stuck your hand out the window. As your speed increases, so do the vibrations in your hand. Trying to keep those fingers steady as the wind whips around them at 75 mph gets pretty tricky, right?

You've just had a quick lesson in unsteady aerodynamics, something engineers are researching and testing on a much larger scale and with supersonic speeds using wind tunnel technology. The wind tunnel tests, recently conducted at NASA's Ames Research Center in Moffett Field, Calif., will be used to enhance the design and stability of the Space Launch System (SLS), NASA's new heavy-lift launch vehicle.

The SLS capability is essential to America's future in human spaceflight and scientific exploration of deep space. Only with a heavy-lift launch vehicle can humans explore our solar system, investigate asteroids and one day set foot on Mars.

"The aeroacoustic tests we just completed at Ames are all about unsteady aerodynamics," said John Blevins. Blevins is the lead engineer for aerodynamics and acoustics in the Spacecraft & Vehicle Systems Department at NASA's Marshall Space Flight Center in Huntsville, Ala., where the SLS Program is managed for the agency. "Local vibrations can have a major impact on the rocket and critical hardware."

"You don't fly hardware, especially with people on board, unless you can verify the environments they fly in," he added. "There are standard practices we've learned from past successful programs. Wind tunnel testing is a cost-effective way to set the requirements needed for all the rocket's components to sustain the flight."

Four models of three different crew and cargo variations of the SLS, including the 70-metric-ton (77 ton) configuration, were tested in a series of wind tunnels at Ames. The 70-metric-ton configuration will be used for the maiden flight of SLS.

Crews of engineers worked around the clock to accomplish the test objectives. "Since vibrations are very localized, they may affect how hardware on the rocket will work," said Andy Herron, lead data analyst for the aeroacoustics tests at the Marshall Center. "Our job is to figure out what these vibrations are, so when another team is designing something -- for example, an avionics box -- we can determine if that hardware needs to be moved or isolated on the vehicle. Or, it may be that the design needs to be tweaked a bit -- all with the goal that the parts will work the way they are intended."

For the tests, the models were affixed with pressure transducers, or sensors, that measure pressures on the model at specific locations. They were first put in the 11-by-11-foot transonic wind tunnel, with wind speeds ranging from Mach .7 to Mach 1.4. A Mach figure represents the ratio of the speed of an object to the speed of sound in the surrounding medium, like air.

Also included in this test series were critical buffet tests, which determine how air affects the vehicle at low frequencies.

The models were then put in unitary 9-by-7 wind tunnel, with winds ranging from Mach 1.55 to Mach 2.5. This test was high-supersonic flow and more focused on local vibrations. Shock waves attach throughout the vehicle at different protuberances, like the feed line or the boosters.

"This is the fastest acoustic test we've ever done, in terms of Mach speed," said Marshall's Darren Reed, lead engineer for the acoustics test. "We tested a wide range of configurations, Mach numbers, angles and more than 4,000 data conditions -- each one with hundreds of transducer measurements."

The next step will be to analyze the test data and share it across the SLS Program for use on the design and development of different components -- including the core stage -- on the actual vehicle. The core stage, towering more than 200 feet tall with a diameter of 27.6 feet, will store cryogenic liquid hydrogen and liquid oxygen that will feed the vehicle's RS-25 engines.

For more information on SLS, visit: http://www.nasa.gov/exploration/systems/sls/


Story Source:

The above story is based on materials provided by NASA. Note: Materials may be edited for content and length.


Cite This Page:

NASA. "Wind tunnel testing used to understand the unsteady side of aerodynamics." ScienceDaily. ScienceDaily, 5 November 2013. <www.sciencedaily.com/releases/2013/11/131105122444.htm>.
NASA. (2013, November 5). Wind tunnel testing used to understand the unsteady side of aerodynamics. ScienceDaily. Retrieved October 21, 2014 from www.sciencedaily.com/releases/2013/11/131105122444.htm
NASA. "Wind tunnel testing used to understand the unsteady side of aerodynamics." ScienceDaily. www.sciencedaily.com/releases/2013/11/131105122444.htm (accessed October 21, 2014).

Share This



More Matter & Energy News

Tuesday, October 21, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Thanks, Marty McFly! Hoverboards Could Be Coming In 2015

Thanks, Marty McFly! Hoverboards Could Be Coming In 2015

Newsy (Oct. 21, 2014) If you've ever watched "Back to the Future Part II" and wanted to get your hands on a hoverboard, well, you might soon be in luck. Video provided by Newsy
Powered by NewsLook.com
Robots to Fly Planes Where Humans Can't

Robots to Fly Planes Where Humans Can't

Reuters - Innovations Video Online (Oct. 21, 2014) Researchers in South Korea are developing a robotic pilot that could potentially replace humans in the cockpit. Unlike drones and autopilot programs which are configured for specific aircraft, the robots' humanoid design will allow it to fly any type of plane with no additional sensors. Ben Gruber reports. Video provided by Reuters
Powered by NewsLook.com
Graphene Paint Offers Rust-Free Future

Graphene Paint Offers Rust-Free Future

Reuters - Innovations Video Online (Oct. 21, 2014) British scientists have developed a prototype graphene paint that can make coatings which are resistant to liquids, gases, and chemicals. The team says the paint could have a variety of uses, from stopping ships rusting to keeping food fresher for longer. Jim Drury reports. Video provided by Reuters
Powered by NewsLook.com
China Airlines Swanky New Plane

China Airlines Swanky New Plane

Buzz60 (Oct. 21, 2014) China Airlines debuted their new Boeing 777, and it's more like a swanky hotel bar than an airplane. Enjoy high-tea, a coffee bar, and a full service bar with cocktails and spirits, and lie-flat in your reclining seats. Sean Dowling (@SeanDowlingTV) has the details. Video provided by Buzz60
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Space & Time

Matter & Energy

Computers & Math

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins