Tunnel 9 efforts in data reduction to benefit Air Force

  • Published
  • By Deidre Ortiz
  • AEDC/PA
ARNOLD AIR FORCE BASE, TENN. --  A member of the AEDC Hypervelocity Wind Tunnel 9 staff in White Oak, Md., has optimized the data reduction process to expedite calculations and display of all data products, an improvement that will be of great benefit to the U.S. Air Force.

The person leading the effort is Mick Marana, a test data engineer for the Tunnel 9 Combined Test Force, and these efforts come at a time when the Air Force is focusing on hypersonic technology as one of its strategic goals in anticipation of several emerging acquisition programs.

“Tunnel 9 has been critical in advancing the technologies useful for missile systems associated with both Tactical Boost Glide and Conventional Prompt Strike,” said John Lafferty, technical director of Tunnel 9. “Since flight experimentation is expensive and takes considerably more time than a ground campaign, Tunnel 9 was front and center in a three-year ground test campaign to accelerate technologies and help narrow the selection of relevant technologies for that potential acquisition program.”

Lafferty added with four major programs needing test data, any increase in productivity or capability has a direct impact on future acquisition and development.

The new data reduction process allows test engineers, analysts and customers the ability to efficiently review the expanded data sets acquired in a single run and develop educated technical decisions based on a more complete understanding of the flow physics.

Joe Coblish, Tunnel 9 lead project manager, explained Marana re-wrote many of the decades-old data reduction routines to bring them up to modern coding standards.

“The higher-level parts of the data reduction codes were converted to MATLAB to speed up the code development cycle, while keeping some of the computation-heavy algorithms in FORTRAN to maintain execution speed. MATLAB's numerical toolsets allowed him to focus on overall efficiency improvements and data display improvements, rather than developing mathematical routines from scratch.”

Tunnel 9 is continually improving and expanding its high-speed data measurement capabilities to observe freestream noise and boundary-layer transition, and using a high-speed data acquisition system collects billions of data points in seconds.

“Efficiency improvements were made to existing pressure fluctuation data reduction codes, allowing results to be available in minutes instead of hours,” Coblish said.

One of the most marked improvements was in the processing of the temperature sensitive paint data.

“The TSP system acquires images of surface temperature time histories on the test article to back out critical heat transfer data to help investigate complete hypersonic flow structures. High-resolution images from multiple cameras are mapped onto a virtual model. Once the image data has been mapped, millions of points on the virtual model are converted to surface temperature and surface heat flux,” Coblish said.

Marana created an in-house mapping software as an improvement over a previous commercial software, increasing automation in the image mapping steps. He also implemented efficiencies in the heat-transfer and post-processing codes.

Before these improvements, reduced TSP data would take anywhere from four to eight hours after the run to process to final heat flux. Now an initial assessment of the TSP data can occur as soon as an hour after a run, allowing the test team the ability for a more thorough assessment of the data before moving onto the next run.

Dan Lewis, project engineer, agreed the benefits of Marana’s new data reduction improvements are much appreciated by the Tunnel 9 team.

“Mick’s capability to provide real time guidance to both the test engineer and customer is observed throughout the course of each Tunnel 9 wind tunnel test,” he said. “His comprehensive knowledge of the data reduction process has resulted in him becoming an integral part of the entire test process. Someone with the ability to support preliminary test planning, real time data analysis and final data processing is invaluable to delivering a successful product.”

-AEDC-