Saheli Patel Defends Dissertation on Modeling and Controlling Flow in Compliant Structures

Saheli Patel has successfully defended her doctoral dissertation, “Experimentally Validated Reduced-order Modeling for the Control of Flow in Compliant Structures,” under the supervision of Jordan Raney, Associate Professor in Mechanical Engineering and Applied Mechanics (MEAM). Her research combines experiments and physics-based modeling to better understand systems in which fluids interact with soft, deformable materials, with applications ranging from soft actuators and adaptive structures to biomedical transport devices.

Fluid flow through rigid systems is well understood, but predicting what happens when fluids move through or around structures that can deform is considerably more challenging. In these systems, the motion of the fluid can deform the surrounding material, while that deformation simultaneously changes the flow. Patel’s dissertation develops experimental and reduced-order modeling approaches that capture the essential physics behind these complex interactions while remaining simple enough to guide the design and control of compliant systems.

Her work spans several systems, including granular jamming actuators, architected granular lattices and valveless impedance pumps. For granular jamming actuators, Patel combined experiments with an elastic-plastic beam-bending model to understand how pressure, geometry and material response influence stiffness, yielding and energy dissipation. She also investigated valveless impedance pumping, in which periodic deformation of a compliant tube generates fluid flow, examining how factors such as actuation, geometry, fluid properties and material compliance affect its nonlinear dynamics.

Patel began her Ph.D. at Penn in fall 2021, when COVID-19 restrictions still limited access to campus and laboratories. She had committed to Penn and Raney’s lab without seeing the lab or meeting its members in person. “It felt like a bit of a gamble at the time, but looking back, I am very glad I made that choice,” she says.

As her Ph.D. progressed, the nature of its challenges changed. Early on, classes, exams, teaching responsibilities and the qualifying exam provided clear milestones. Once those were complete, Patel had to learn how to define her own path forward. “I had to learn how to stay self-driven when there was no longer a checklist, grade or exam telling me what to do next,” she says. “This was arguably much more difficult, but also much more fulfilling.”

That independence also changed how Patel approached research. She entered graduate school expecting to focus primarily on experimental work but gradually expanded into theory and computation. Over time, problems that once seemed intimidating became opportunities to learn new tools.

“One of the most valuable parts of my Ph.D. has been learning that I do not have to be intimidated by a new set of equations or an unfamiliar modeling problem,” Patel says. “I can figure out what I need to learn, work through the physics and finally build the tools I need to answer the question.”

One particularly memorable breakthrough came through a collaborative project with Children’s Hospital of Philadelphia (CHOP). After nearly two years of work, Patel and her collaborators were finally able to reproduce the experimental behavior they had been seeking. When their model began capturing similar behavior, the different pieces of the project came together. “It really felt like all the hard work had paid off and the work was really coming together,” she says.

Other milestones included submitting her first paper and presenting at her first conference, the Biomedical Engineering Society (BMES) Annual Meeting. Attending a biomedical conference outside her lab’s typical research area gave Patel the opportunity to see how researchers from another field responded to her work. She found it especially rewarding to receive thoughtful questions and positive feedback from a new scientific community.

Her experience at Penn extended beyond research. Patel enjoyed teaching and mentoring students, including contributing to the structure of a statics course and mentoring another teaching assistant who later assumed a senior role. She also served as president of the Mechanical Engineering Graduate Association (MEGA) as the graduate community rebuilt following the pandemic, helping organize social and professional events that brought students together.

As she considers opportunities in engineering research and development and biomedical consulting, Patel is looking forward to applying that approach to a broader range of open-ended problems and seeing projects through from beginning to end.

For students considering a Ph.D. in MEAM, Patel emphasizes finding the right advisor and research environment. She encourages prospective students to visit laboratories, speak with current students and ask direct questions about mentorship and working styles. She also advises students to embrace the independence that comes with doctoral research without assuming they need to solve every problem alone.

“One of the useful skills I have taken away is learning when it is worth struggling through something yourself and when a five-minute conversation with someone who has already gone through the struggle can save you hours,” she says.

Patel extends her gratitude to Raney for his guidance throughout her Ph.D., as well as her lab members and collaborators for their ideas and support. She also thanks Prashant Purohit, Professor in MEAM, for his support as MEAM Graduate Group Chair and a member of her committee, particularly for bringing new energy to projects and encouraging her to see them through to submission.

Finally, Patel thanks her family and her husband, Vivek Sharma, whom she met during her Ph.D.

“We met each other during the Ph.D. and went through this experience alongside one another, which meant having someone who understood this whole process without me always needing to explain it,” she says. “I feel very lucky to have found a partner who is so aligned with me in how we want to live our lives and the kind of life we want to build together.”