Arindam Banerjee, Paul B. Reinhold Professor and Department Chair, Mechanical Engineering and Mechanics (MEM) at Lehigh University, heads the Turbulent Flow Lab, which occupies part of a lower floor in Packard Lab on Lehigh’s main campus. During the summer of 2026, it’s the research home of undergraduate mechanical engineering student Miriam Heter, who will be a senior at the University of Rochester in New York in the fall and is part of the summer 2026 cohort of STEM-SI, and Mohd Hanzla, a fifth-year graduate student in MEM who is preparing to defend his dissertation in the fall semester, as well as several other graduate students and postdocs. Miriam and Mohd work together in the lab, which focuses on turbulent fluids–those whose particles move in ways that are irregular, chaotic, with changing pressure and speed, like ocean waves swirling around your ankles at the beach. (The opposite is laminar flow, which has a steady and regular movement, like maple syrup poured over pancakes.) The lab’s goal is to contribute to the scientific understanding of the interactions of turbulent flows with tidal turbines.
Mohd works on tidal turbines as part of Banerjee’s involvement with the Atlantic Marine Energy Center (AMEC), a four-university group consisting of the University of New Hampshire (UNH), Lehigh University, Stony Brook University, and the Coastal Studies Institute of North Carolina, funded by the Department of Energy (DOE) to advance the marine energy industry and research the blue economy. That’s the use of the ocean and its energy–which includes tidal action–to contribute to the economic well-being of a community.
Tidal turbines, which are kind of like underwater wind turbines, can contribute reliable energy to a community, because they harvest the power of tides. As any beachgoer knows, tides ebb and flow about every 12 hours, unaffected by weather and atmospheric conditions as are other natural energy sources such as sun and wind. The motion of tides can be turned into electricity, with only a few hours of down time per day.
Within the AMEC consortium, the University of New Hampshire runs full-scale devices, including tidal turbines, and gathers real-time field data from the devices. Mohd and other AMEC researchers can use UNH’s data, scaled down, in a lab to run experiments and perform more testing than it’s possible to do in the field, largely because the lab can control conditions more carefully. As Mohd says, “We are able to scale down some of those features in our lab water tunnel, then we can actually do a lot more testing that can inform us about design improvements.” The other AMEC universities also collaborate, and the group convenes periodically to share information.
The Tidal Turbulence Testing Facility, housing a water tunnel at Lehigh, sits on a platform in the center of the room. Mohd describes it as “a recirculating closed loop water tunnel, 2 meters long and 0.6 meters wide.” It can be set up to generate various speeds, up to a flow of up to one meter per second. The lab has an active grid that can generate freestream turbulence in the water. All of this allows Mohd to generate the turbulent flows and perform measurements that monitor the structural health of turbine blades.
Mohd notes that the lab works on both application and fundamental aspects of turbulent flow. Application-wise, he points to the lab’s scaled-down experiments using UNH’s data. These experiments can, he says, result in improved designs for tidal devices as well as turbine farm optimizations (a group of turbines in a fast-flowing area of water).
From the fundamental perspective, the generation of turbulent flows is critical and challenging. Similar labs typically have a tank but no capacity for homogeneous or non-homogeneous turbulence generation, or they have turbulence generation but no capacity for periodicity/non-stationary turbulence or waves. TurbLab is trying to bring together four elements: turbulence, periodicity, waves, and shear (a change in velocity within the fluid). That’s a complex combination, as well as a unique one; few labs consider all four factors. Doing this can open the field to a new level of experimentation.
While Mohd focuses on adding complexity to the water tunnel, Miriam directs her work on one key aspect: the waves created on top of the turbulence. Specifically, she is measuring them, using a tool called a sound-based wave transducer. The instrument is new to the lab, but its basic technology is familiar: sound. The lab has, Mohd says, used an acoustic Doppler velocity meter for close to eight years, making them familiar with the calibrations. The new transducer also uses sound as a way to measure the waves on top of the turbulence.
So far, Miriam has been reading relevant literature and setting up the transducer. She will be the first lab member to use it, and says that the “eventual idea is to be able to use it to characterize the waves and the wave heights to help with this project.” Although she may become the lab’s expert on the use of the transducer by the end of the summer, she’s very new to lab research. “I've never done research before,” she says, “so this is a new experience.” That’s exactly the situation STEM-SI, a ten-week undergraduate research program at Lehigh, exists to address. Now in its sixth year, STEM-SI introduces 30 to 40 undergrads per year to an active research lab and faculty and/or graduate student mentors. While working in TurbLab is Miriam’s first formal research experience, she has taken fluid dynamics courses at the University of Rochester, and has experience in setting up experiments in her classes and in the U Rochester Baja SAE cars. Coincidentally, the team’s advisor, Christopher Muir, graduated from Lehigh (PhD ʼ96).
She first joined Baja with friends, but stayed because, she says, “It was just really cool to see the hands-on way that everybody was doing stuff in the club. And you get to actually build stuff–you get to manufacture things, you can do design.” She discovered that she wanted to design, and now she’s on the design board for the club and is involved in the building of the car. As an engineer, she seems to be motivated more by the hands-on aspect of research, and that should be an asset in the lab as it optimizes tidal turbine research.
Neither Miriam nor Mohd has firm post-graduation plans, and both are adamant that they want to keep their options open. Mohd has just published an article based on his dissertation research in Physical Review Fluids, and Miriam will be graduating from the University of Rochester next spring. And with their contributions to the Turbulence Flow Lab, the future of tidal turbines is more secure.