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Modeling Software for Microgravity Fluid Mechanics
Modeling Software for Microgravity Fluid Mechanics

We’ve all seen the images of astronauts aboard the International Space Station floating from room to room, spinning cartwheels in the near-weightless environment of a low earth orbit, their movement appearing so fluid it seems almost effortless. What most of us have never seen and very few have probably even thought about are the myriad systems operating behind the scenes in those fantastic images—the systems that went into designing the Space Station, those that helped carry its parts into orbit, and those maintaining its serviceability and supporting the lives of the people aboard, systems that circulate air, pump fuel, recycle water.

You may have wondered about how materials move in microgravity environments, or imagined drops of water floating in the vacuum of space, but have you ever thought about how you would get materials to move where you wanted them to, when you wanted them to, in the absence of gravity, and what if the movement of those materials was a matter of life and death?

Dr. Mark Weislogel, Professor of Thermal and Fluid Sciences in the Maseeh College of Engineering and Computer Science, and his team have spent a lot of time thinking about just this problem. The result of their endeavors is the Surface Evolver Fluid Interface Tool, or SE-FIT software, an innovative modeling program developed with the support of a grant awarded to Dr. Weislogel by NASA that shows engineers how fluids move and behave in low gravity where there’s no up or down.

SE-FIT software is an easy to use, open-source program available through Portland State University that accurately demonstrates the way fluids behave in microgravity within a specific container. While it’s not the only program of its kind, the SE-FIT software was designed with the faults of another open-sourced surface modeling program in mind.
“I was tired of having difficult access to numerical solutions for free surfaces,” said Dr. Weislogel, speaking of the SE-FIT software’s predecessor. “Using the existing Surface Evolver technology made solving for the free surface of a liquid almost more trouble than it was worth: it was a hassle and a put-off, and there was a large energy barrier to get over in order to use the program.”

Thanks to the work of Dr. Yongkang Chen, a Research Associate in Mechanical & Materials Engineering, and a few others, with the new SE-FIT software an engineer can, as Dr. Weislogel puts it, “spin around in a chair, put in a geometric test cell, and check it out to see how the liquid would behave.”

While the program was designed to show engineers how liquids behave in space without gravity, it has applications here on Earth as well. To explore those applications the Office of Innovation & Intellectual Property at Portland State University connected Ph.D. student Ryan Jenson, a SE-FIT software user and beta-tester, with the Department of Engineering & Technology Management’s New Venture Management course, a class in which students explore emerging technologies and create commercialization strategies for those technologies. Together Mr. Jenson and students in the New Venture Management class developed a plan to apply the SE-FIT software’s modeling capacities to electronic packaging, petroleum, automotive, casting, and printing industries, to name but a few. Companies like HP, Xerox, or any company that requires the management of liquids on a micro-scale would find the SE-FIT software a useful design ally.

“The software, designed for spacecraft development, will work for sponges, wicking surfaces, and fluid passageway development as well,” Dr. Weislogel said.
“The real-world value of this program is to quickly and efficiently calculate different configurations,” Mr. Jenson added. “When you talk to people in the industry, what they want is something that’s usable. Engineering time is more valuable than computational time.”
The SE-FIT software, whose development was funded by NASA, is now available through a Portland State University license that allows “people who aren’t experts in fluid dynamics to model complex geometries and get a feel for what the liquid would do for zero cost compared to what it would cost to build an experiment,” Dr. Weislogel noted.

In the future, Dr. Weislogel would like to see the SE-FIT software users designing their own catalogues of prebuilt geometric test cells and adding them to a library of geometries available to users like the NASA scientist studying the behavior of water on Mars and the engineer at Xerox developing the next generation of printer technology. But Dr. Weislogel has even greater hopes for the SE-FIT software. Sometime in our near future he envisions SE-FIT software helping engineers take us beyond low Earth orbit and safely into the vast reaches of interplanetary space.

Authored by Shaun McGillis
Posted May 5, 2012