Why did you choose to study at Illinois?

During my undergraduate studies, I became deeply interested in experimental fluid mechanics through my involvement in several research projects. This experience motivated me to pursue doctoral studies in experimental fluid dynamics. As I explored programs, I was particularly looking for a multicultural, interdisciplinary research environment that would broaden both my academic and personal perspectives while providing exposure to cutting-edge work.

The University of Illinois Urbana-Champaign stood out to me for its strong reputation in fluid mechanics and experimental research, as well as its access to world-class facilities and collaborative institutes such as the Beckman Institute for Advanced Science and Technology. I was especially drawn to the opportunity to work on large-scale experimental projects, including the development of the largest vertical particle-laden turbulent flow facility in the United States, and to engage with advanced measurement techniques like magnetic resonance imaging-based flow diagnostics.

Equally important was the academic culture at Illinois. The emphasis on both high-impact research and the development of teaching and mentoring skills strongly aligned with my long-term goal of becoming a professor. Opportunities to serve as a teaching assistant and to mentor undergraduate students through semester-long research projects in AE 298 allowed me to actively build these skills. I also recognized that a successful academic career requires balancing research, teaching, and mentorship, each demanding its own set of skills and commitment. Programs like the Mavis Future Faculty Program, which provides structured training in these areas, were an important factor in my decision.

Another key consideration was the support and flexibility offered during my admission in 2020, at the height of the COVID-19 pandemic. The university accommodated remote learning from India despite significant time zone differences, and the guidance and responsiveness of the faculty and administrative staff made a strong impression on me. This level of support reinforced my confidence that U. of I. would be an environment where I could both succeed and grow.

Please tell me about your research.

My thesis research focuses on understanding how inertial particles, heavier than the carrier fluid, behave when suspended in turbulent flows. This falls within the broader class of multiphase flows known as particle-laden turbulent flows, with a specific focus on the subsonic incompressible flow regime. These systems are relevant to a wide range of applications, including aircraft operations in dusty environments, spray combustion, industrial multiphase reactors, and particle-laden heat exchange within solar panels. Inertial particles, through multiscale interactions with the underlying turbulent flows, preferentially concentrate, forming distinct regions of high particle concentration, clusters, and low concentration, voids. We investigated both the spatial structure and temporal evolution of these particle clusters across a wide range of flow and particle conditions.

Time-resolved particle tracking velocimetry measurements were conducted in a newly developed vertical particle-laden turbulent channel flow facility in Talbot Laboratory to capture the temporal evolution of particle clusters. We have developed novel data-analysis tools for particle cluster identification and tracking, and, using these tools, statistically characterized macroscopic cluster properties such as size, topology, growth and decay rates, and lifetime, as well local cluster particle dynamics.

My thesis work primarily relies on established optical and probe-based flow measurement techniques. Through this work, I understood the limitations of traditional methods, particularly in capturing the full 3D structure and dynamics of complex flows. Therefore, besides my primary Ph.D. research, I got involved in several projects involving MRI measurements of flow velocity and concentration in collaboration with Beckman Biomedical Imaging Center. This included participating in biennial magnetic resonance velocimetry challenges in collaboration with five universities worldwide, aimed at benchmarking gated phase contrast-MRI for complex 3D transient flows and coupled velocity and concentration measurements for pollutant dispersion in model urban canopy. I have also contributed to MRI studies of natural ventilation dynamics in complex open-air structures and built environments, where we measured both velocity and concentration. These efforts led to the establishment of long-term collaborations between our group and the U.S. Military Academy at West Point to conduct MRI experiments at Beckman for the cadets' annual capstone projects.

What were unusual challenges you experienced along the way?

Building a new experimental lab from scratch is inherently challenging and, in many ways, comparable to building a startup, requiring iterative problem-solving, resourcefulness, and persistence. Throughout the development of the vertical particle-laden turbulent channel, we encountered several technical challenges that eventually led to important breakthroughs.

One of the most demanding tasks was the assembly and alignment of the vertical tunnel sections spanning three floors.

Achieving micron-level alignment across a structure approximately 12 meters in height required meticulous design, careful execution, and precise coordination. Ultimately, the system was vertically aligned within 0.1 degree, reflecting the level of accuracy necessary for reliable experimental measurements. This was made possible through close collaboration with the aerospace machine shop team, particularly Dustin Burns and Greg Milner. Another significant challenge arose from electromagnetic interference generated by the variable frequency drives of the blowers, which corrupted our measurement signals. Through persistent troubleshooting and a hands-on, iterative approach, we were able to identify the sources of noise and implement effective mitigation strategies, allowing us to obtain reliable experimental data.

Ensuring uniform dispersion of inertial particles across the channel width presented an additional challenge. After extensive trials over the course of a summer, we developed an effective solution by strategically placing computer cooling fans in a diamond configuration within the particle feeding section to disperse particle streams and achieve uniform seeding.

In parallel, our work on MRI-based experiments at the Beckman Institute introduced a different set of logistical and experimental challenges. Our MRI concentration measurement setup required handling approximately 600 gallons of water, distributed across three large totes of 275 gallons each. Integrating this setup within the Beckman facility without obstructing access to imaging equipment or disrupting other research activities required careful planning and coordination. Additionally, degassing such a large volume of water was nontrivial. To address this, we utilized an innovative solution using flow cavitation through converging-diverging nozzles to effectively remove dissolved air. Managing such large fluid volumes was both demanding and dynamic; despite careful precautions, occasional spills were inevitable, requiring constant preparedness and adaptability during experimental preparation.

What activities did you do outside of studying?

Outside of academic activities, I have been actively involved in the Bengali cultural student organization, Abol Tabol, contributing to the organization of various cultural events since its inception. I served as vice president during the 2023–2024 academic year.

I have a strong interest in drama, regularly performing in two productions each year with roles in both acting and directing. Besides this, I enjoy spending my free time swimming, fishing and travelling.

 

What's next for you?

In the near term, I will continue my research as a postdoctoral scholar in the Turbulent and Multiphase Flow Research Lab over the coming year. Looking ahead, my long-term goal is to pursue an academic career by joining a faculty position in India.

What advice would you give someone considering getting an advanced degree?

Pursuing a Ph.D. degree is a long-term commitment that demands both perseverance and genuine passion for your field. The research process is often nonlinear, marked by challenges, setbacks, and only occasional breakthroughs. Maintaining consistency, focus, and resilience through these fluctuations is essential for long-term success.

At the same time, it is a uniquely rewarding journey that fosters deep intellectual growth, independence, and problem-solving ability. If you are willing to embrace the challenge with patience and commitment, it can be an immensely fulfilling experience, so make the most of it.

What's on your bucket list for the next five years?

I want to travel with my entire family and spend meaningful time together exploring new places. I am also keen to learn and develop my skills in gardening.