While much existing work focuses on simplified or isolated mechanisms in controlled environments, real-world systems involve coupled interactions, geometric complexities, and confinement effects that critically influence particle behavior. My doctoral research develops unified theoretical frameworks for understanding the transport of micro- and nanoparticles driven by coupled active and passive phoretic processes, highlighting the effects of particle shape, actuation strategies, and hydrodynamic interactions.
This work encompasses three interrelated topics that advance understanding of transport phenomena in microscale systems:
(a) Hydrodynamic and geometric effects on phoretic motion:
We study how particle geometry, mechanical actuation, and boundary proximity influence phoretic transport. Using slender body theory and Lorentz’s reciprocal theorem, we model bent rod microswimmers actuated by hinge articulation and self-diffusiophoresis. For reciprocal hinge motions, Purcell’s scallop theorem is validated, predicting zero net displacement, while non-reciprocal strokes generate complex trajectories sensitive to stroke amplitude, shape asymmetry, and actuation frequency. Pure chemical propulsion leads to circular motion, whereas combined mechanical-chemical actuation yields richer dynamics. Near solid boundaries, wall-induced hydrodynamic and chemical coupling modifies these dynamics, emphasizing the importance of confinement.
Relevant Publications: (1) Ganguly, A., & Gupta, A. (2023). Going in circles: Slender body analysis of a self-propelling bent rod, Physical Review Fluids, 8(1), 014103; (2) Raj, R., Ganguly, A., Becker, C., & Gupta, A., Motion of an active bent rod with an articulating hinge: exploring mechanical and chemical modes of swimming. Front. Phys. 11:1307691.
(b) Unified theoretical framework for phoretic propulsion:
Traditional models of passive diffusiophoresis involve solving coupled PDEs for solute concentration, interaction potentials, and fluid flow—computationally intensive at moderate interaction lengths. Active diffusiophoresis often assumes a prescribed phoretic slip velocity, which may lack physical clarity. We reconcile these approaches by deriving a unified mobility formulation expressing particle motion via phoretic body forces, bypassing full flow-field solutions. This framework recovers classical results for external diffusiophoresis and electrophoresis and, in the thin interaction layer limit, reduces to slip-velocity expressions common in active particle literature. Applying this to Janus particles reveals how catalytic cap size and interaction length influence propulsion, with hemispherical caps achieving maximal speeds. We find that slip-based models tend to overestimate velocities at moderate interaction lengths. Extending this framework to spheroidal particles, we quantify how geometric anisotropy modulates phoretic response in both passive and active regimes.
Relevant Publication: Ganguly, A., Roychowdhury, S., & Gupta, A. (2024). Unified mobility expressions for externally driven and self-phoretic propulsion of particles. Journal of Fluid Mechanics, 994, A2.
(c) Shape-dependent inertial transport of particles in physiological flows:
Transport of microparticles in physiological environments involves complex fluid dynamics and non-spherical geometries. Left Ventricular Assist Devices (LVADs) improve survival in heart failure patients but raise risks of thromboembolic complications such as stroke. Predictive modeling of embolus transport requires incorporating particle shape effects absent in classical models like the Maxey-Riley equation, which assume spherical particles. Our research extends this framework to spheroidal emboli by deriving generalized equations of motion for rotation and translation in non-uniform, finite Reynolds number flows using asymptotic expansions and reciprocal relations. We incorporate inertial lift corrections near vessel walls, capturing how embolus shape, size, and wall proximity influence trajectories. By integrating this model into patient-specific computational fluid dynamics pipelines, we aim to improve understanding and prediction of embolic dynamics beyond current clinical imaging capabilities.
Together, these studies unify the physics of microscale transport driven by chemical gradients, mechanical actuation, and non-uniform background flows, with a focus on the interplay between particle shape and the environment. The theoretical tools developed, inform design principles for programmable microscale motion, relevant for biomedical microbots, targeted drug delivery, microfluidic technologies, and cardiovascular health.
Bio-sketch:
Arkava Ganguly is a Ph.D. candidate in Chemical Engineering at the University of Colorado Boulder specializing in transport phenomena, multiscale modeling, and electrokinetics with a focus on microscale particle transport and propulsion. His research develops predictive, physics-based models that integrate chemical-mechanical actuation, particle shape effects, and complex hydrodynamics, enabling advances in microrobotics, targeted delivery, and biomedical embolus transport. Arkava brings strong expertise in CFD, continuum modeling, and data analytics using Python, MATLAB, and COMSOL, complemented by industrial experience in process optimization; mechanical design and structural analysis; and statistical modeling. He is skilled in translating fundamental research into applied solutions, collaborating across experimental and computational teams, and supporting scalable design and validation of advanced transport systems relevant to biomedical, environmental, and industrial applications.
Notable Awards: (1) American Institute of Chemists Graduate Student Award, University of Colorado Boulder (2025); (2) Teets Family Endowed Graduate Fellowship in Nano-technology, University of Colorado Boulder (2023); H.L. Roy Memorial Gold Medal, Jadavpur University (2020).
Arkava is looking for relevant engineering or R&D roles in - (1) Microfluidics and Biomedical Devices; (2) Advanced Materials and Colloids; (3) Chemical Manufacturing; (4) Multiphysics/Chemical Engineering Software and other fields aligned with his doctoral and pre-doctoral experience.
Research Interests: Modeling and Simulation of Fluid Mechanics and Multiphysics phenomena, with a focus on