Space shuttle experiment to provide insights into turbulence, heating

Mar 23, 2009 by Emil Venere
Brad Wheaton, left, and Peter Gilbert, graduate students in aeronautics and astronautics at Purdue, stand near a segment of a special type of wind tunnel capable of running quietly at hypersonic speeds. Experiments using the wind tunnel are enabling engineers to study how air turns from "laminar," or smooth, to turbulent. Findings will help researchers determine how to control deadly friction and heating in the design of future spacecraft, advanced missiles and "hypersonic" aircraft powered by engines called scramjets. Credit: Purdue News Service photo/Andrew Hancock

A Purdue University aerospace researcher helped shape plans to install a new experiment currently on the space shuttle Discovery to collect data for controlling deadly friction and heating in the design of future spacecraft.

Discovery was launched March 15 on a 13-day mission.

A special "roughness element" was installed among the shuttle's heat-shielding panels. The element is raised about a quarter of an inch and will be used to study how air turns from "laminar," or smooth, to turbulent. Data from the research will help design the heat shield for NASA's Orion crew exploration vehicle, a vital component in future missions to the moon and Mars.

Data from the experiment also will help engineers design "hypersonic" aircraft that travel faster than Mach 5, nearly 4,000 mph, said Steven Schneider, a professor in Purdue's School of and Astronautics.

The faster an aircraft flies, the greater the friction and dangerous heating. Such heating damaged the leading edge of the heat-shielding system on the space shuttle Columbia, causing it to burn up as it entered the atmosphere in 2003.

"We have been arguing in favor of doing some sort of space shuttle flight experiment, and after the Columbia accident there was a lot more attention paid to aero heating," said Schneider, who aided NASA in planning the experiment.

Data will be collected while the shuttle re-enters the Earth's atmosphere at the conclusion of the mission. The landing is scheduled for Saturday (March 28).

A better understanding of the transition from smooth to turbulent airflow is critical to the design of spacecraft and hypersonic aircraft and engines called scramjets, or ramjets.

Purdue researchers also are using the only capable of running quietly at and have conducted experiments to yield data for designing advanced missiles such as the Falcon HTV-2 and an advanced aircraft called the X-51A, which is powered by scramjets. The X-51 project is led by the Air Force Research Laboratory and the Defense Advanced Research Projects Agency.

The experiment on Discovery, which also is planned for two additional shuttle missions, will complement wind tunnel experiments and findings from computational models.

"It is very desirable to conduct an experiment like this under real flight conditions on a real shuttle instead of a model," Schneider said. "But no single experiment, whether on the ground or in flight, can give you everything you want."

Air flowing over a hypersonic vehicle should generally be as smooth as possible to reduce friction and heating, which increases drag and necessitates a heavier thermal protection system for the vehicle's thin metal skin.

At the same time, researchers also need to learn how to create turbulent airflow to operate the scramjet engines. Scramjet designs use a scooplike cowl on the underbelly, where air rushes into the inlet of the engine's combustor. It is critical for air entering the inlet to be turbulent at hypersonic speeds, or the engine could "unstart," causing it to crash, Schneider said.

For this reason, air has to be converted to a turbulent flow before entering the inlet. This conversion is accomplished using a raised strip of metal placed near the inlet to "trip" the air from smooth to turbulent. Wind tunnel tests are helping engineers better understand this "roughness-induced transition."

Purdue researchers are using a roughness element inside the wind tunnel to study the airflow transition. Detailed wind tunnel measurements are to aid other researchers who are developing computational models capable of simulating the shuttle experiment.

The quiet wind tunnel operation is critical for collecting data to show precisely how air flows over a vehicle's surface in flight. No other wind tunnel runs quietly while conducting experiments in airstreams traveling at Mach 6, Schneider said.

Source: Purdue University (news : web)

Explore further: Could 'Jedi Putter' be the force golfers need?

add to favorites email to friend print save as pdf

Related Stories

AFRL Proves Feasibility Of Plasma Actuators

Apr 24, 2006

The Air Force Research Laboratory is laying the groundwork to develop revolutionary hypersonic aerospace vehicles. AFRL is examining the feasibility of replacing traditional mechanical actuators, which move to control an ...

Guinness World Records Recognizes NASA Speed Record

Aug 31, 2004

Guinness World Records has recognized the world speed record set by NASA's hypersonic X-43A aircraft earlier this year in an experimental flight over the Pacific Ocean. Using a scramjet engine, the unpiloted, 12 ...

Recommended for you

Could 'Jedi Putter' be the force golfers need?

Apr 18, 2014

Putting is arguably the most important skill in golf; in fact, it's been described as a game within a game. Now a team of Rice engineering students has devised a training putter that offers golfers audio, ...

Better thermal-imaging lens from waste sulfur

Apr 17, 2014

Sulfur left over from refining fossil fuels can be transformed into cheap, lightweight, plastic lenses for infrared devices, including night-vision goggles, a University of Arizona-led international team ...

User comments : 0

More news stories

NASA's space station Robonaut finally getting legs

Robonaut, the first out-of-this-world humanoid, is finally getting its space legs. For three years, Robonaut has had to manage from the waist up. This new pair of legs means the experimental robot—now stuck ...

Ex-Apple chief plans mobile phone for India

Former Apple chief executive John Sculley, whose marketing skills helped bring the personal computer to desktops worldwide, says he plans to launch a mobile phone in India to exploit its still largely untapped ...

Filipino tests negative for Middle East virus

A Filipino nurse who tested positive for the Middle East virus has been found free of infection in a subsequent examination after he returned home, Philippine health officials said Saturday.

Egypt archaeologists find ancient writer's tomb

Egypt's minister of antiquities says a team of Spanish archaeologists has discovered two tombs in the southern part of the country, one of them belonging to a writer and containing a trove of artifacts including reed pens ...