Evaluating Ship and Submarine Designs
Lisa Minnick had a choice after earning her master’s degree in ocean engineering from Virginia Tech in 2006. Would she take a job in private industry, lured by “wining and dining” and a potentially big paycheck, or would she grab an opportunity to work at the largest and most comprehensive ship research facility in the western world, where the U.S. Navy’s ships, submarines, military watercraft, and unmanned marine vehicles are evaluated?
She chose the latter and, for four years, has been happily employed as a civilian ocean engineer at the Naval Surface Warfare Center (NSWC) Carderock Division in West Bethesda, Md.
Minnick participates in hands-on testing of scaled ship and submarine models in Carderock’s one-of-a-kind towing tanks and water channels. The towing tanks, which are housed in an amazing structure almost a mile long, include a deep-water basin, shallow-water basin, and a high-speed tank where scale models can be tested at speeds up to 50 knots.
A separate building houses a Rotating Arm facility and a Maneuvering and Seakeeping Basin that has been called an “instant ocean.” It is a rectangular freshwater tank, equal in length to a football field and almost twice the width, with pneumatic wavemakers capable of generating model-scale waves with heights equal to those that occur during a hurricane. This basin is used to study the effect of wave conditions on ships, submarines, and ocean platforms.
“We study both new ship designs and the performance of ships already in the fleet,” Minnick explains. “The seakeeping performance of a ship is how it responds to the ocean environment. We want to make sure a ship or submarine performs as expected — for example, that it won’t capsize in heavy seas — and to keep the crew safe.” Currently, Minnick participates on a research team evaluating two competing ship designs. To compare their performance, the models are rigged on carriages that tow them along the tanks to evaluate resistance performance both in calm water and waves.
“We are also interested in what goes on under the water, specifically how the water moves around the hull of a ship or submarine,” says Minnick. Using a technique called particle image velocimetry, the researchers seed the water with small reflective particles and use a laser to illuminate the particles. High-speed photography allows them to track the flow of the water around a hull, paying special attention to any vortices created by a ship in motion. The flow of the water can influence how a ship will react in certain conditions. “We are one of the only facilities in the world that do this,” she adds.
Minnick was first introduced to NSWC Carderock in college. “If you’re in ocean engineering, you know about Carderock,” she says. Minnick interned for two summers at the lab following her sophomore and junior years. While in grad school, she tried something different: an internship with a large petroleum company. “It was interesting to get an idea of what private industry is like,” Minnick notes. What she learned is that an engineer is less likely to do hands-on engineering and more likely to manage engineering projects. Although such jobs can be rewarding, Minnick is glad she chose government research. “What we do at Carderock is unique. I’ll be in the middle of a test and I’ll think, ‘Hey, this is something I learned in school and now I am applying it!’
“There is so much going on here at Carderock that you can’t be involved in anywhere else. This may be the only job I ever have,” Minnick says almost incredulously.
Her job also allows her to be active in First Lego League (FLL) after-school robotics programs for 4th and 5th graders. “I help them build their robots, solve challenges, and get ready for international FLL competitions,” Minnick explains. Her team, sponsored by the National Defense Education Program, also participates in the regional STEM challenge led by a sister Navy laboratory, NSWC Indian Head Division. “The kids get so excited at the robotics competitions, and I kind of feel like a proud mom!” Minnick says. “I really enjoy outreach. It’s nice, once a week, to see engineering through little kids’ eyes. It keeps me energized.”
In her spare time, Minnick transforms herself from an engineer to an artist — a leap she says is not that far. “You can see engineering in my paintings. I tend toward the abstract, and my paintings are geometric and shape-oriented. I like creating order out of chaos; it’s a different creative outlet for me,” she says.
Who does Minnick credit for starting her down the path she so thoroughly enjoys? It was her dad, who is not an engineer himself but could see that his daughter, from a young age, wanted to understand the world and liked to figure out why things work the way they do.
Photo courtesy of NSWC Carderock Division