Science meets art in Brown engineering course, as students capture the beauty of fluid mechanics

Using the scientific principles behind fluid mechanics, students in a School of Engineering course produced stunning imagery brought to life via high-speed photography.

PROVIDENCE, R.I. [Brown University] — In a ground floor laboratory inside the Barus and Holley building at Brown University, students gather around a brightly colored mix of fluids. Every few seconds, they watch as droplets fall into a beaker holding a white, blue and neon pink blend, sending liquid splashing upwards.

The students note each impact and pattern — sometimes with marvel — before quickly deliberating and tinkering with the experiment for a more precise splash.

Given the laboratory setting and the precision the students seemed to be aiming for, it’s easy to assume the group had purely scientific goals in mind as they repeated the process again and again. Their true purpose, however, had a much more aesthetic slant.

Conducting the experiment as part of Engineering 0350: Art Fluid Engineering, the students’ goal was to capture stunning imagery, using high-speed photography, of the different ways liquids can splash. The end product is meant to show how the work of scientists and engineers, and the fundamental laws and principles they rely on, can also be applied to artistic creation.

Taught by engineering professor Roberto Zenit, the course, along with its more advanced counterpart ENGN 1350, is known for how it merges two distinct disciplines — visual art and fluid mechanics. In that sense, the course is both an art and engineering class. It features traditional lectures on the scientific concepts that underpin fluid mechanics and artists who visit to help students take those principles and manipulate them as an artist would.

“In this class, I teach fluid mechanics, but without equations,” Zenit said. “Students learn about classic fluid principles like momentum, viscosity and flow, but they also learn how those can that be used to create images and other elements with aesthetic value.”

Lab projects throughout the semester give students the chance to put what they learn about both art and fluid mechanics into action.

“The course keeps its identity as a rigorous engineering class where you learn a concept and then have to test it out in the lab,” Zenit said. “The difference is that the end product is critiqued on its aesthetics.”

Making a splash

The splash photography project represents one of the most iconic challenges in all of fluid mechanics. The practice started in the late 1800s and early 1900s when scientists were first able to capture fast-moving droplets hitting surfaces. It has both scientific merits as well as artistic value.

The practice also requires a fair measure of technical know-how and artistic skill to pull off. An experiment by Brown undergraduates Lucian Sharpe, Sofia Gilroy, Kiara Vong and Himanssh Pettie, who took the course in the spring, showed why.

The group set out to capture a mushroom-like structure that erupts vertically from the water when multiple droplets impact the surface at just the right time and in just the right place. It’s incredibly difficult to capture, even for skilled splash photographers.

“It's much more random,” said Sharpe, a senior concentrating in mechanical engineering. “It's really hard to get that second drop to hit perfectly.”

During initial meetings, the group hashed out a plan. Arriving at the lab, the students got many of the logistical elements out the way. They set up a beaker, mixed their colorful batch of fluids, made sure the tubing and camera were in place and set parameters on a programmable Arduino controller to coordinate the timing of the drops and trigger the camera.

From there, it was all about experimentation. They spent the bulk of the time on adjustments as they repeated the process hundreds of times over a two-day period.

For instance, they found the camera’s shutter and flash were activating too quickly to capture exact moment of the splash they wanted, so they delayed it by a millisecond or two. They saw the droplets were too far apart, and then adjusting them further as they became too close. At one point, they used their cell phones to record the process in slow motion to get a better idea of the mechanics they were seeing so they could plan what to tweak.

“There was a lot of trial and error,” said Gilroy, a junior concentrating in environmental science. “There were a lot of parameters we had to work through to start getting consistent images.”

This was where theoretical concepts from class sessions on viscosity, surface tension and hydrodynamic instability proved handy. When the vertical jet that erupts from a droplet was too low, for example, they knew right away one thing they could do was raise the syringe needle higher so the drop hit with more force.

In total, the students ended up with close to 300 images, but it could easily have been 600 without their prior knowledge from the lectures.

“Understanding the basics of the theories from class helped us fine tune a lot faster,” said Pettie, a senior engineering and applied mathematics concentrator.

The final image the group submitted was the mushroom effect they were aiming for. It was voted the best image by the class and was recently featured in Physics Today. Another equally spectacular image they made was one where a droplet passed through a bubble without breaking it. No matter how much they tried to duplicate the success, the students couldn’t re-create the image.

“The fact that we got such a perfect crown structure contained within the bubble, everything just felt right with that picture,” Pettie said. “We tried shooting the exact same thing seconds after, and we didn't get anything like it.”

At the end of the semester, students displayed their fluid mechanics inspired artwork from the entire course and final projects during a public art exhibit in the lobby of Barus and Holley.

“The experience and artwork provide a unique look at both disciplines,” Pettie said.