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Special Joint Mechanical Engineering Department and Levich Institute Seminar – Thursday, 11/20/2025Thursday, 11/20/2025
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ABSTRACT The collision and coalescence of particles settling in a flow field are central to both environmental and industrial processes, from raindrop formation in clouds to aerosol aggregation in reactors. Predicting collision efficiency remains challenging because near-field hydrodynamic interactions strongly retard particle approach, while additional interparticle forces are required to achieve contact. In the gaseous environment of clouds, continuum hydrodynamics breaks down at small separations, and non-continuum effects dominate. We show that these effects, rather than van der Waals forces, enable finite collision efficiencies for cloud droplets. By coupling sedimentation, background flow, and near-field interactions, our work provides a more physically consistent basis for modelling particle collisions across engineering and atmospheric systems. BRIEF ACADEMIC/EMPLOYMENT HISTORY: Anubhab Roy is an Associate Professor in the Department of Applied Mechanics, Indian Institute of Technology Madras (IIT-M), Chennai, India. In 2013, he received his PhD in Engineering Mechanics from Jawaharlal Nehru Centre for Advanced Scientific Research (JNCASR), Bengaluru. He was a postdoctoral fellow at the School of Chemical and Biomolecular Engineering, Cornell University, before joining the Fluid Mechanics group at Applied Mechanics IIT-M. MOST RECENT RESEARCH INTERESTS: Suspensions, Cloud microphysics, Geophysical Flows |
Last Updated: 11/19/2025 08:01