By Shannon Yentzer
In the vast field of fluid mechanics, researchers strive to unravel the intricate dynamics and forces that govern the behavior of fluids. Raúl Bayoán Cal, an esteemed mechanical engineer and recent winner of the David E. Wedge Excellence in Teaching Award, has dedicated his career to studying these physical phenomena, and recently in the context of space exploration with direct terrestrial applications.
His groundbreaking work at Portland State focuses on disentangling the complex forces that occur in nature by harnessing the unique environment of microgravity. With the aid of a recent almost $1 million grant from the National Science Foundation (NSF) and Center for the Advancement of Science in Space (CASIS) joint grant that covers future experiments at the International Space Station, Cal and his team aim to shed light on the behavior of particles in fluids, ultimately contributing to a wide range of practical applications and scientific advancements.
One of the strengths of PSU’s Maseeh College is its diversity. Students, faculty, and staff come from a wide array of locations and follow sometimes meandering and challenging paths. Cal’s background and educational journey are no exception. The Puerto Rico native earned his Bachelors and a Ph.D. in Mechanical Engineering at Rensselaer Polytechnic Institute. After conducting experiments in Gothenburg, Sweden, he returned to the U.S. for a post-baccalaureate at Johns Hopkins before joining the faculty at Maseeh College.
Cal’s continued fascination with fluid mechanics led him to offer objective insights into the behavior of fluids. While exploring various areas within the field, Cal discovered his true passion for turbulence, a subject that lies at the core of his research at PSU. His interest in turbulence was sparked during his undergraduate research, and it has since evolved into a multi-faceted exploration of fluid mechanics spanning from renewable energy to volcanism. Recently, Cal has gained interest in microgravity environments and how they can affect fluid mechanics.
Cal’s experiments aim to study small capillary forces in microgravity. “There are a lot of physical phenomena that are difficult to explain on Earth because of the forces that are happening. Gravity tends to have a way of obscuring other things that you could otherwise see. By turning gravity off, you can see all of these other phenomena that were tied to your problem in the beginning,” he says.
The allure of studying fluid mechanics in space lies in the ability to observe and comprehend phenomena that are otherwise entangled by Earth’s gravity. By operating in a microgravity environment, scientists can isolate specific forces and gain a deeper understanding of their individual contributions. Cal’s project at PSU centers around utilizing a drop tower, a facility resembling a refrigerator, to conduct experiments that offer videotaped glimpses into the behavior of particles in fluids. During a 2.1-second drop, Cal’s team films the movement of particles in water, enabling them to analyze and comprehend the dynamics at play.
While Cal’s research specifically focuses on particles and their agglomeration or dispersion, the implications of his work extend far beyond this realm. Practical applications abound, from the study of algal blooms to microplastic movement in water to volcanic eruptions to pollen transportation. Understanding how particles interact in fluid environments and respond to imposed frequencies has critical implications for mitigating health hazards and addressing environmental challenges, and the knowledge gained from these studies can enhance existing models and improve predictions.
Cal’s project at PSU funded by the NSF spans three years, during which time his team will collaborate with a company to prepare and launch their experiments into space aboard the International Space Station (ISS) to have access to longer microgravity periods. The team will be able to communicate with the ISS astronauts as the experiments progress, and they are working with a company, Zin Technologies, to get the experiments ready for space.
As the project progresses, Cal envisions the refinement of models and the application of knowledge gained from space experiments to further improve our understanding of fluid dynamics on Earth. With PhD students Natalie Frank, Karl Cardin, and Facundo Cabrera-Booman, a postdoctoral researcher, eagerly participating in this pioneering research, the excitement and potential for groundbreaking advancements in fluid mechanics are palpable.
I encourage all students to take the path of doing research. It’s a great way to explore your interests and find out what you’re truly passionate about.
— Raúl Bayoán Cal
The relentless pursuit of understanding fluid mechanics in the unique context of space exploration in Cal’s lab holds immense promise for the scientific community. By disentangling the forces that occur in nature and leveraging microgravity environments, his research aims to unlock the secrets of physical phenomena, shedding light on particle behavior in fluids.
“We’re exploring a lot of things involving fluid mechanics and space,” Cal explains. “By turning gravity off, we can understand these forces that are happening, whether it’s at the air-water interface or in the bulk of the fluid. This will ultimately help us solve complex problems and advance our understanding of fluid mechanics.”
As Cal’s research continues to push the boundaries of what we know about fluid mechanics, it is clear that he is an engineer and teacher with a contagious enthusiasm for discovery.
“I encourage all students to take the path of doing research,” he says. “It’s a great way to explore your interests and find out what you’re truly passionate about.”
This advice applies to students outside of Maseeh College as well. Cal’s team will be doing outreach with 6-9-year-olds, working with an elementary school teacher to develop a curriculum to introduce gravity concepts by focusing on the behavior of fluids in space. These young scientists will even design and perform their own drop tower experiments, engendering a love of STEM in the next generation of budding engineers.
Shannon Yentzer is the Communications Manager of the Maseeh College of Engineering and Computer Science.