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Lab News -- February 2, 2007

February 2, 2007

LabNews 02/02/2007PDF (650KB)

Sandia-developed MiniSAR flies for first time on Lockheed Martin unmanned aerial system

By Chris Burroughs

The Sandia-developed miniaturized synthetic aperture radar (MiniSAR) flew for the first time on a Lockheed Martin unmanned aerial system (UAS) recently, taking images in flight.

“This has been our goal all along — to have the MiniSAR fly on a UAS,” says Sandia researcher Dale Dubbert (5345). He, together with George Sloan (5345) and Armin Doerry (5342), created the approach for a miniaturized synthetic aperture radar. Working with them were other engineers from multiple departments, playing key roles in the development and innovation activities. Eventually the intent is to have the MiniSAR be used for reconnaissance missions.

MiniSAR flew on Lockheed Martin’s small SkySpirit UAS at the Minnesota National Guard test facility. On Oct. 19, through the closely coordinated efforts of Sandia and Lockheed Martin, the SkySpirit soared to nearly 3,000 feet, becoming the first UAS to successfully transmit real-time, four-inch resolution SAR imagery from a Class III unmanned aerial vehicle. During four different mission demonstrations, the SkySpirit transmitted MiniSAR images, capturing actionable data in two operational modes, including focused area circle-mapping and broad area strip-mapping. Multiple imaging passes were post-processed to demonstrate coherent change detection used to identify changes over time.

First autonomous flight

This demonstration marked the first time an autonomous flight of a small tactical UAS has captured SAR data of this type and resolution. The use of a MiniSAR, which is being produced by Rockwell Collins, Inc., could greatly enhance a ground unit’s surveillance capabilities with a UAS. It can capture high-resolution images through weather, at night, and in dust storms.

Dale, George, and Armin started developing the 30-pound MiniSAR about three years ago, incorporating a number of key technologies, including mechanical design, digital miniaturization, RF miniaturization, and navigation expertise. MiniSAR was made possible after the gimbal and electronic teams got the unit down to its diminutive size. It consists of two major subsystems: the antenna gimbal assembly (AGA) — the pointing system that consists of the antenna, gimbal, and transmitter — and the radar electronics assembly (REA) — the signal generator, receiver, and processors. The AGA beams the radio frequency and receives it back. The REA is the electronics package that generates the radar signals, controls the system, processes the data, and transforms it into an image.

“In the past small classes of UASs could carry payloads of 50 pounds, which limits them to video or infrared cameras,” Dale says. “The smaller MiniSARs will let them carry additional sensors that together will provide a very detailed reconnaissance picture.”

MiniSAR was initially tested on a Twin Otter aircraft owned by NNSA. The October test flight on the Lockheed Martin SkySpirit UAS demonstrates that the MiniSAR could be deployed by tactical unit commanders for real-time reconnaissance, regardless of smoke, dust, heavy rain, or nighttime conditions.

Rick Udicious, vice president and general manager of Lockheed Martin’s Tactical Systems business, says his company understands the military’s need to provide tactical support for the warfighter.

“The need for small unmanned systems that meet emerging mission requirements for agility, affordability, and the next generation of resolution accuracy is a key element in extending the tactical capabilities of US forces,” he says.

Flying MiniSAR on Lockheed Martin’s small SkySpirit UAS will help meet that need. -- Chris Burroughs

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CRF team awarded more than six million hours of supercomputing processor time to better understand flame phenomena

By Mikes Janes

Jackie Chen (8351) and a team of collaborators have been awarded more than six million hours of computing time on the Cray X1E and XT3 supercomputers at Oak Ridge National Laboratory to study flame phenomena. The award comes from DOE’s Office of Science and is part of the department’s 2007 Innovative and Novel Computational Impact on Theory and Experiment (INCITE) program, will allow cutting-edge research and design of virtual prototypes to be carried out in considerably less time than it would take using conventional computing systems.

Jackie’s team, Chun Sang Yoo (8351), David Lignell (8351), Ramanan Sankaran (Oak Ridge, 8351), Evatt Hawkes (8351), and Phil Smith (University of Utah), is working on an array of direct numerical simulations that will provide a fundamental understanding of key processes such as flame stabilization, flame structure, extinction, ignition, and soot formation. The high-quality simulated benchmark data will also be used by combustion modelers to develop predictive engineering models used to design future combustion devices. These processes underlie fuel-efficient low-temperature combustion engine designs for transportation and lean premixed combustion for stationary power generators. An increase in automobile fuel efficiency from 30 to 45 percent, experts say, would result in a savings of three million barrels of oil per day of the 20 million consumed for transportation with a corresponding decrease in CO2 emissions.

“Our project has strong applications and science impact, which given the importance of energy conservation and efficiency, very likely makes it all the more attractive to the Office of Science,” says Jackie, who works in Sandia’s Combustion Research Facility. Simulations developed by her and her team provide data to validate mixing and combustion models in engineering-level simulations of combustion devices. The award-winning project is titled “High-Fidelity Numerical Simulations of Turbulent Combustion — Fundamental Science Toward Predictive Models.”

The DOE Office of Science awarded 45 projects and a total of 95 million hours of computing time on some of the world’s most powerful supercomputers as part of the INCITE program. DOE Under Secretary for Science Raymond Orbach presented the awards at the Council on Competitiveness in Washington, D.C.

CPU hours valuable

Supercomputers are playing an increasingly important role in scientific research by allowing scientists to create more accurate models of complex processes, simulate problems once thought to be impossible, and to analyze the increasing amount of data generated by experiments. For example, a project receiving one million hours could run on 2,000 processors for 500 hours, or about 21 days. Running a one-million-hour project on a single-processor desktop computer would take more than 114 years.

“The Department of Energy’s Office of Science has one of the top 10 most powerful supercomputers in the world and four of the top 100 and we’re proud to provide these resources to help researchers advance scientific knowledge and understanding,” Energy Secretary Samuel Bodman said.

“I look forward to witnessing the promise of these efforts as some of the world’s greatest thinking minds use some of the world’s greatest thinking computers.”

Launched in 2003, the INCITE mission is to advance American science and industrial competitiveness. These awards will assist in that mission by supporting computationally intensive, large-scale research projects and awarding them large amounts of dedicated time on DOE supercomputers.

The projects, with applications from aeronautics to astrophysics, consumer products to combustion research, were competitively chosen based on the potential impact of the science and engineering research and the suitability of the project for use of supercomputers.

“One of the most important aspects of the INCITE program is that the resulting knowledge will largely be available, so that the information and technologies can be used by other researchers, further broadening the impact of this work,” Orbach said.

“Our scientific leadership underpins nearly every aspect of our economy and by making these resources available to a broad range of science and engineering disciplines; we believe the resulting work will make us more competitive in the years and decades to come.”

For 2007, the projects were awarded time at DOE’s Leadership Computing Facilities at Oak Ridge National Laboratory in Tennessee and Argonne National Laboratory in Illinois, the National Energy Research Scientific Computing Center at Lawrence Berkeley National Laboratory in California, and the Molecular Science Computing Facility at Pacific Northwest National Laboratory in Washington. -- Mike Janes

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Wind turbine blade designed by Sandia and partner is first of its kind

By Chris Burroughs

A new wind turbine blade design that Sandia developed in partnership with Knight & Carver (K&C) of San Diego promises to be more efficient than current designs. It should significantly reduce the cost-of-energy (COE) of wind turbines at low-wind-speed sites.

Named “STAR” for Sweep Twist Adaptive Rotor, the blade is the first of its kind produced at a utility-grade size. Its most distinctive characteristic is a gently curved tip, termed “sweep,” which unlike the vast majority of blades in current use, is specially designed for low-wind-speed regions like the Midwest. The sites targeted by this effort have annual average wind speeds of 5.8 meters per second, measured at 10-meter height. Such sites are abundant in the US and would increase by 20-fold the available land area which can be economically developed for wind energy.

Sized at 27.1 meters — almost three meters longer than the baseline it will replace — the blade improves energy capture at lower wind speeds. Instead of the traditional linear shape, the blade features a curvature toward the trailing edge, which allows the blade to respond to turbulent gusts in a manner that lowers fatigue loads on the blade. It is made of fiberglass and epoxy resin.

“This design allows the blade to twist more than traditional designs, thus relieving some of the effects of gusty turbulent wind on blade life,” says Tom Ashwill (6333), who leads Sandia’s blade research efforts. “This then allows us to grow the blade length for the same rotor, providing for increased energy capture of 5-10 percent and yet retaining the same expected fatigue life.

The Knight & Carver contract is part of the Low Wind Speed Technology (LWST) project that targets wind sites that are not the strongest but plentiful. In late 2005 DOE and Sandia awarded Knight & Carver the $2 million contract that includes $800,000 in K&C cost share. Because of budget reallocations, this project was the only one of several LWST projects to receive 2007 funding.

Sandia’s role in the project has been in directing design and test planning. The Knight & Carver team provided the detailed design and blade fabrication.

The first STAR blade was tested last week at Knight & Carver’s fabrication facility in San Diego to determine its bending and twist behavior due to static loads. Natural frequencies were also measured. This data will be compared to design simulations to determine how well the design concept performs. Four additional blades will be fabricated in the first quarter of 2007 — three of which will be flight-tested on a turbine in Iowa.

Other members of the design team are Dynamic Design of Davis, Calif.; MDZ Consulting of Clear Lake Shores, Texas; University of California, Davis; and NSE Composites of Seattle, Wash.

“The DOE interest and funding are a big step for us,” Tom says. “We’ve been pushing for the incorporation of innovative concepts into utility-scale blades for some time now as a way of reaching program goals of lowered cost of energy.”

He adds that the continued increase in the average size of utility-grade wind turbines may come to an end before all efficiencies are wrung out unless blade weight growth (which is nonlinear) can be reined in. The challenge is to develop new concepts that reduce the rate of weight growth, such as the swept STAR blade.

Other weight-reducing concepts such as carbon spar caps, off-axis carbon fibers that facilitate bend-twist coupling, and new “structural” airfoils have been incorporated at a smaller scale in 9-meter-long prototype blade being flight-tested at Sandia’s test site in Bushland, Texas, at the

US Department of Agriculture’s Agricultural Research Service facility. -- Chris Burroughs

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