Students help to devise ‘home labs’ for remote fluids course

An introductory fluid mechanics class in the School of Engineering couldn’t be taught in-person this fall, but a group of undergraduates worked over the summer to make sure hands-on lab experiments remain part of the course.

PROVIDENCE, R.I. [Brown University] — Brown University engineering professor Roberto Zenit’s introductory fluid mechanics class is chock-full of laboratory experiments that give students a firsthand feel for fluid flows and the forces that drive them. The labs, Zenit says, are important in helping students connect equations and abstract concepts to actual phenomena they can see and experience.

But when the COVID-19 pandemic made it impossible to hold a class of this size in-person, Zenit had to rethink how he would put the class together.

“When we entered this new way of life and this new way of teaching, we knew immediately we’d need to change our classes, particularly the engineering labs,” Zenit said. “But we didn’t know immediately how we were going to do it.”

So Zenit enlisted a group of undergraduate students who worked remotely this summer, supported in part by undergraduate research funding from Brown, to develop new “home labs” for fluid mechanics. The idea was to think of items that students are likely have handy in their houses, apartments or dorms, and use them to perform experiments that drive home key fluid mechanics concepts.

The result was a fresh set of new labs for the course, tailor-made for remote learning. A ping-pong ball suspended in the airstream from a hair dryer can demonstrate drag force and turbulent jets. A glob of honey oozing outward on a baking sheet offers a chance to calculate viscosity. A plastic tube between two buckets of water can teach about pipe-flow, a concept critical in hydraulics and other applications.

To complement the everyday items used in the experiments, Zenit assembled a small component board with pressure and flow sensors, as well as a small CPU that can be plugged into a laptop. The boards, along with a few custom-made tubes and valves, are being mailed to each student in the class this fall — whether they’re studying remotely somewhere across the globe, or logging in from a residence hall on campus or local apartment — thanks to funding support from the School of Engineering.

Image of a circuit board
Each student in the class will be mailed a board with a variety of sensors and a small computer processor.

The job this past summer for the students — rising sophomores Advay Mansingka and Amick Sollenberger and rising junior Portia Tieze — was to test and tweak the experiments, figuring out what works, what doesn’t and what students would be able to do easily from home. Also active in the project were master’s students Mithun Ravisankar and Ajay H. Kumar, and Tom Powers, a professor on engineering who is co-teaching the class this fall.

“It was cool to learn these concepts by doing them first,” said Mansingka, who worked on the project from his home in India. “You can get a more intuitive understanding of things like how wind speed changes with the distance from a hair dryer, which would probably be harder to understand if it were just an equation.”

The hair dryer experiment may seem simple — just a ball floating on a column of air — but the phenomena captures plenty of important ideas on fluid mechanics, Zenit says. The ball stays within the column of air because of Bernoulli’s Principle — the observation that jets of moving air have lower pressure than the surrounding air. And the students can use key equations to describe other aspects of what they’re seeing.

“For example, you can measure the distance between the ball and the hair dryer, and if you know the weight of the ball you can calculate the flow speed,” Zenit said. “Or depending on how you do the experiment, you might know the flow speed and then you can calculate the weight of the ball.”

Not every experiment worked as initially planned. For example, Zenit originally envisioned a way to connect a small plastic tube to a garden hose as part of a pipe flow experiment. But Sollenberger, working remotely in South Kingstown, R.I., discovered that the setup wasn’t going to work.

Image of a flow meter
A custom-made flow meter, first developed by Zenit as part of a DIY ventilator project during the early part of the pandemic, will be used by students for pipe flow experiments.

“Amick ended up blowing up the pressure sensor because the pressure from the hose was just too high,” Zenit said. “She felt bad, but I thought it was great. We learned something and we found a different way to do the experiment that turned out to be much better.”

Like Mansingka, Sollenberger said helping to conceive a new way of making the class successful was a rewarding experience.

“Doing hands-on projects has always been my favorite part of taking a course, and it was really sad last semester when everything moved virtually so abruptly,” she said. “So it was really exciting for me to be able to be at home and do these experiments.”

And thanks to the work that Sollenberger and her colleagues put in this summer, the 90-plus students signed up for the course this fall will get to do those experiments too. Zenit says he’s happy that these integral parts of his class will remain intact during remote learning.

“The easiest path would have been to skip the labs altogether,” Zenit said. “But we’re not necessarily interested in easy. We want to have the best class we can for our students.”