Tech

September 18, 2013

NASA Dryden engineers capture dramatic supersonic shockwave images

Supersonic shockwaves are clearly visible in this dramatic schlieren image of a NASA Dryden F/A-18 aircraft flying at a speed of Mach 1.1, and an altitude of 44,000 feet during a GASPS flight.

 

Elusive schlieren images of supersonic shockwaves emanating from NASA F-15 and F/A-18 aircraft flying at supersonic speeds were captured during recent pilot proficiency flights.

The images were gathered by a twin telescope and digital camera system on the ground at NASA’s Dryden Flight Research Center to manually test the Ground-to-Air Schlieren Photography System, or GASPS, that was developed by MetroLaser, Inc. under a NASA Small Business Innovation Research project. Schlieren photography is a technique that enables imaging of airflow, with special illumination making changes in air density—in this case the density of the shockwaves—apparent.

“Our team was able to photograph truly spectacular images showing the shockwaves of full-scale supersonic aircraft in flight,” said Ed Haering, Dryden’s GASPS principal investigator.

This dramatic schlieren image of supersonic shockwaves streaming from NASA Dryden’s F-15B aircraft was captured while it was flying at Mach 1.38 at 44,000 feet altitude during a GASPS flight.

“For new quiet supersonic aircraft designs, computer simulations and wind tunnel tests are used to model how to minimize the loudness of the sonic booms, but the simulations and wind tunnel tests have challenges in accurately modeling the flow around engine inlet and tail regions,” Haering explained. “We can use these images to validate our computer simulations and wind tunnel tests, giving us confidence that we can properly design supersonic civil aircraft of the future. Then we will be able to fly over land at about double the speed of current civil aircraft without bothering people on the ground,” he added.

Engineers used a thumb trigger to manually snap digital images when the aircraft passed in front of the sun. Later tests will most likely use aircraft GPS tracking transmitted to the GASPS system on the ground to automatically activate their shutters for more precise imaging.

Previous schlieren photography used an elaborate series of lenses, bright backlighting, and other devices to capture supersonic shockwaves on film as darker or lighter streaks against high-contrast backgrounds like the edge of the sun. Versions of this ground-to-air technique used in the 1990’s required extremely precise alignment of the optics as well.

In contrast, the GASPS project uses just a telescope and a digital camera, leaving the difficult aspects of the work to be performed post-flight using image processing software. This improved method greatly relaxes the precision needed, with the post-mission digital processing of the imagery employed to visualize the shock wave patterns.

With the sun as the light source, supersonic shockwaves are clearly visible in this spectacular schlieren image of NASA Dryden’s F-15B Research Testbed aircraft as it streaks by at Mach 1.2 at an altitude of 40,000 feet during a GASPS flight.

Schlieren imaging provides a clearer understanding of the location and relative strength of supersonic shockwaves. This represents another tool in the growing toolbox of techniques used by NASA researchers designed to characterize sonic booms.

This latest project continues a long series of sonic boom reduction research by NASA.  The 10th anniversary of the NASA/Northrop Grumman F-5E Shaped Sonic Boom Demonstration (SSBD) project’s first reduced sonic boom flight was Aug. 27, marking another milestone in NASA and industry’s path to lower sonic booms. A new NASA aeronautics book, “Quieting the Boom: the Shaped Sonic Boom Demonstrator and the Quest for Quiet Supersonic Flight,” by Lawrence R. Benson details the project. The book was recently posted on-line as a NASA eBook at http://www.nasa.gov/connect/ebooks/nasa-ebook-quieting-the-boom/.

The GASPS project is supported by the NASA Aeronautics Research Mission Directorate’s High Speed Project, which is working to reduce the intensity of sonic booms in order to make commercial supersonic flight over land practical.




All of this week's top headlines to your email every Friday.


 
 

 

Headlines July 7, 2015

News: F-35 loses dogfight to fighter jet from 1980s – A new report alleges that an F-35A was defeated by the very aircraft it is meant to replace.   Business: South Korea selects Airbus for $1.33 billion tanker contract – European aerospace giant Airbus won a $1.33 billion deal June 30 to supply air refueling...
 
 
U.S. Chamber of Commerce photograph

Boeing, Embraer to collaborate on ecoDemonstrator technology tests

U.S. Chamber of Commerce photograph Frederico Curado, president & CEO of Embraer, and Marc Allen, president of Boeing International, at the Brazil-U.S. Business Summit in Washington, D.C. The event occurred during an offici...
 
 
Untitled-2

Tactical reconnaissance vehicle project eyes hoverbike for defense

The U.S. Army Research Laboratory, or ARL, has been exploring the tactical reconnaissance vehicle, or TRV, concept for nearly nine months and is evaluating the hoverbike technology as a way to get Soldiers away from ground thre...
 

 
Air Force photograph by SSgt. William Banton

Upgraded AWACS platform tested at Northern Edge

Air Force photograph by SSgt. William Banton Maintenance crew members prepare an E-3G Sentry (AWACS) for takeoff during exercise Northern Edge June 25, 2015. Roughly 6,000 airmen, soldiers, sailors, Marines and Coast Guardsmen ...
 
 
LM-Legion

Lockheed Martin’s Legion Pod™ takes to skies

Lockheed Martin photograph by Randy Crites Lockheed Martin’s Legion Pod recently completed its first flight test, successfully tracking multiple airborne targets while flying on an F-16 in Fort Worth, Texas. Legion Pod was in...
 
 
Air Force photograph by SSgt. Marleah Robertson

First Marine graduates Air Force’s F-35 intelligence course

Air Force photograph by SSgt. Marleah Robertson Marine Corps 1st Lt. Samuel Winsted, an F-35B Lightning II intelligence officer, provides a mock intelligence briefing to two instructors during the F-35 Intelligence Formal Train...
 




0 Comments


Be the first to comment!


Leave a Reply

Your email address will not be published. Required fields are marked *

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <s> <strike> <strong>