Undersea Warfare The Official Magazine of the U.S. Submarine Force. Winter 2004 U.S. Submarines... Because Stealth Matters Cover for Winter 2004
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Submarine Force Technology: Building a better way of life for the future. Photo: The applied Research Laboratory's Garfield Thomas Walter Tunnel at Penn State has helped in the development of advanced instrumentation such as laser measurement systems.
by JOC Michael Foutch
Photo caption follows

The tunnel, dedicated in 1949, was so large the building that houses it on campus was constructed around it. According to Penn State, the idea behind the tunnel was to provide a unique hydrodynamic facility to study cavitation phenomena in designing wake-adapted propellers that have led to quieter Navy propulsors. The tunnel has also been used to calibrate model-installed acoustic pressure and unsteady force transducers.

Photos provided by ARL, Penn State

Equipped with the most advanced weaponry and surveillance capabilities in the history of naval warfare, the Submarine Force patrols the world’s oceans to defend our nation and preserve the American way of life. But the same technical advances now propelling the undersea force into the future may also have significant potential for making that way of life even better for us all.

Investments in military technology have often spilled over into everyday life to
benefit all Americans. For example, the Internet grew from the desire of the Defense Advanced Research Projects Agency (DARPA) to design a network for allowing computers at different universities to communicate with each other without a central control node. As a result of the adaptation of this military technology for everyday use, today’s wired world shares information at speeds unimagined only a few decades ago.

On the other hand, not every military development transferred to civilian use has been high technology. In World War II, a product called “duck tape” was used for water-proofing ammunition cases. Soldiers also found it useful for repairing jeeps, guns, and even aircraft, and the tape went on to commercial fame as “duct tape,” for sealing seams in air ducting and an infinite variety of other household tasks.

Thanks to the know-how of a number of scientists who have spent their professional lives on advancing submarine technology, a number of other improvements in the quality of civilian life may be close to realization right now.

One place where this work is underway today is a nondescript group of buildings on a leafy campus in a rural valley of Pennsylvania. Some of these promising new technologies are still in the minds of scientists strolling the halls or sketched on a drawing board or computer screen. Others are tinkered with in the noisy laboratories inside. And a few are already in the fleet, under test by Submariners who will soon be using them in the near future. Unexpectedly, a handful of these new ideas may eventually be adapted for home use in cooling ice cream or building a quieter lawnmower.

During World War II, the Navy mobilized scientists and engineers from universities nationwide to join the war effort, and one group was located at Harvard’s Underwater Sound Laboratory. These acoustics experts made major advances in wartime sonar systems for detecting German U-boats and acoustically-guided homing torpedoes to sink them.

With the end of the conflict, many of the organizations that were mobilized for the war effort returned to their civilian work. The Navy, however, was determined to continue its wartime joint ventures with Harvard and other universities. When the director of the Harvard research team, Dr. Eric Walker, left for a position at Pennsylvania State University, the Navy asked him to continue his undersea warfare research on its behalf, a partnership that continues to this day at Penn State’s Applied Research Laboratory (ARL).

“We work with the submarine program in developing a range of technologies to meet the needs of the fleet, especially research on propulsor noise and new types of propulsors and propulsion systems,” said Dr. Edward Liszka, ARL’s director. “This is a technology-focused lab – that’s our product. We believe you have to get out there and demonstrate new ideas, establish credible performance, and address issues that often prevent implementation of new technology in the fleet. Our goal is to get the technology out there and get people to use it. In that kind of development and testing, we often find issues that are fixable in the next technology upgrade.”

Other universities across the country, such as Johns Hopkins and MIT, join Penn State in supporting the Navy by employing some of the nation’s finest scientific talent to maintain the Submarine Force on the cusp of the possible. In these efforts, Navy-funded scientists use ARL equipment such as the Garfield Thomas Water Tunnel, the most active closed-loop test facility in the world, which serves a purpose similar to that of an aeronautical wind tunnel in studying hydrodynamics and hydroacoustics problems. This 48-inch diameter tunnel is so large that at the time of its construction in 1949, the building it is housed in had to be constructed around it. When operating at a velocity of 35 knots, more than a million gallons of water shoots through the test section every three minutes.

“We’re looking to get the most out of the things we do, Dr. Liszka said. “The underlying science and physics we develop from submarine research often give us the opportunity to do things differently in other fields.”

One such example is using ideas from submarine technology to build a better lawnmower.

Talk to ARL’s Dr. Courtney Burroughs for a few minutes, and he will explain that the blades under a power mower are similar to those of a ship’s propeller. His work to build quieter submarines gave him an idea. “The propeller blade under the deck of the mower is the thing that makes most of the noise. But a lawn mower works in a much more hostile environment than the ocean,” he said. Nevertheless, his team applied to lawnmowers some of the same techniques they would use to study a noisy propeller. “We put sensors on the blades to look for unsteady pressure and impedance discontinuities,” Dr. Burroughs explained. Understanding these phenomena led to a contract to develop a quieter mower.

Moreover, if lawnmower blades are analogous to a ship’s propellers, then so are other fans – ranging from the ones used to scrub dust out of the air in a coal mine to those employed in a breathing machine to help people suffering from sleep apnea. But Dr. Burroughs was not satisfied with constructing a quieter fan for bedroom and coal-mine use. Using sensor data on unsteady pressure and broadband noise that he gathered from testing propellers in the ARL Water Tunnel, he discovered another use for his findings.

“Auto tires,” he said. “There’s a fairly violent reaction where the rubber meets the road.” So, by embedding sensors inside some steel-belted radials and measuring the impacts of the underlying asphalt as if it were water rushing past the edges of a propeller blade, the same science used in reducing the noise of submarine propulsion could lead to a quieter ride on the highway.