Project Openings
Open positions for Postdocs and PhD students
Some research areas in which there are openings are listed below. If you are interested in pursuing a PhD at the Chemical Engg. department of IIT Bombay please visit the admissions webpage.
1. Polymers in turbulence
An Indo-French IFCPAR/CEFIPRA postdoctoral position is available to work on this topic, along with me and Dario Vincenzi (Univ. Cote d'Azur, France). Follow this link for more information about the project and for application instructions.
Adding even a miniscule amount of dissolved polymer into a fluid can have a dramatic impact on the way it flows. If the flow is turbulent (high-Reynolds-number) to begin with, then the polymer can strongly modify the turbulent eddies and reduce the drag force---an effect which is used to reduce energy losses in pipelines---or even make the flow laminar. Polymers can also destabilize a low-Reynolds-number steady flow and make it unsteady and chaotic: a regime known as elastic turbulence which has application in enhancing mixing in microchannels and oil recovery from underground reservoirs. Although observation of these intriguing phenomena have been available for decades, our understanding of the turbulent dynamics of dilute polymer solutions remains poor. Models for such viscoelastic fluids can at best explain qualitative features of the dynamics, but fall short of being able to quantitatively predict experimental observations. This multi-part project will address this issue by first developing a detailed understanding of the dynamics of individual polymer molecules in turbulence, and then using this new understanding to develop improved continuum models. The tools that will be used include direct numerical simulations of the solvent combined with brownian dynamics simulations of the polymers, stochastic theory, and continuum modelling. There are opening for postdocs, multiple PhD students and Masters students for this work. One exciting opportunity is the IITB-Monash PhD program where we have a PhD project open, along with Prabhakar Ranganathan (Monash University): https://www.iitbmonash.org/wp-content/uploads/2021/02/IMURA0966.pdf.
Collaborators: Prabhakar Ranganathan (Monash University, Australia) and Dario Vincenzi (Univ. Cote d'Azur, France).
2. Traffic flow dynamics
Traffic in India is notorious for being highly unruly and disorganized. Is this solely due to a lack of discipline on the part of drivers, or does the high density and heterogeneous nature of Indian traffic (mix of scooters, cars, buses and trucks) contribute to the emergence of collective chaotic dynamics? With the number of vehicles on our roads increasing each year, it is important to understand the fundamentals of Indian traffic flow in order to engineer solutions to problems like traffic congestion that plague our major cities.
Traffic flow is distinguished from other many-body problems of physics, like granular flow, by the fact that the individual agents are intelligent---drivers have memory, learned behaviours, and the freedom to violate rules. Our work aims to combine multi-agent models with reinforcement learning algorithms to understand how patterns of traffic emerge and evolve, with a focus on Indian traffic and its unique features.
Collaborators: Danny Raj (Danny Raj, IISc, Bangalore).
3. Microflows: Interfacial forces and elasto-hydrodynamics
The flow of layered fluids in microchannels plays a key role in several micro devices aimed at solvent extraction, chemical processing, bio-chemical diagnosis, etc. Despite the viscous, low-Re nature of these flows, quite complex dynamics can arise due to an interplay between the two fluids, as well as interfacial forces acting at the liquid-liquid interface, or elastic forces in cases where the fluids are separated by a membrane (as in membrane extraction or the organ-on-a-chip device, see adjoined figure). Our work in this area will focus on developing and analysing mathematical models of these systems, in order to understand the physical principles governing theri dynamics. This work will point to strategies for improving system performance. Moreover, the elasto-hydrodynamic fluid-membrane-fluid problem serves as a simple model system for understanding how low-Re viscous flows interact with a thin, deformable solid plate/membrane, which is relevant to flow past cells and in the heart and lungs.
4. Pattern Formation: fundamental issues
The goal of this project is to address fundamental questions about spontaneous spatio-temporal patterns that emerge as a consequence of instabilities in nonlinear, multi-scale systems. Examples of such patterns include cloud streets, waves on films in coated-wall reactors, channeling in magma flows, and oscillations in stirred chemical reactors. Some questions of interest are: How does the pattered state get triggered from a non-patterned (possibly time varying) base state? How is a specific pattern selected from noisy disturbances? How do multiple instability modes interact across scales? These questions will be investigated in the context of concrete physical systems, but with a focus on understanding general principles. As an example, the article referenced below addresses the issue of pattern selection in a multi-layer liquid film, which serves as a stage for complex interactions between two distinct interfacial instability modes.
J. R. Picardo and R. Narayanan, Interfacial pattern selection in defiance of linear growth, Journal of Fluid Mechanics, 829, 345-363, 2017