LIFD Early Career Researcher Spotlight: Yatin Darbar

Thesis title: Mixing Dynamics of Droplets of Complex Fluids

School/ Faculty: CDT in Fluid Dynamics

Supervisors: Mark Wilson, Harvey Thompson, David Harbottle, Thomas Sykes (Oxford)

Tell us a bit about yourself

I am currently in the final year of PhD at the CDT in Fluid Dynamics. Before Leeds I graduated from the University of Birmingham with an MSci in Mathematics. During this time I specialised in applied mathematics, with fluid mechanics modules being by far my favourite. This led to me doing my final year research project investigating the static and quasi-static equilibrium figures of a liquid bridge.

When I’m not thinking about fluids I enjoy running, watching live music, playing the guitar and trying anything that looks cool!

What is your research about?

Chemical reactions within coalescing droplets play a crucial role in numerous emerging technologies aimed at creating innovative materials. However, effective mixing between droplets is essential for these reactions to occur. Various factors such as droplet size, material properties, heat transfer, and chemical reactions can significantly influence the dynamics of droplet coalescence, thereby affecting internal mixing processes. The primary objective of my PhD is to gain a comprehensive understanding of the mechanisms underlying mixing in coalescing droplets, particularly those relevant to inkjet technologies.

Traditionally, experiments investigating the internal dynamics of droplets have utilized millilitre-sized droplets due to ease of analysis. However, extrapolating these findings to the inkjet scale, which operates at orders of magnitude smaller, presents challenges. To address this limitation, my research focuses on developing a numerical simulation method capable of accurately capturing droplet coalescence dynamics while exploring the impact of diffusion, material parameters, heat transfer, and chemical reactions on internal mixing.

So far in my project I have used the open-source computational fluid dynamics software OpenFOAM to develop a numerical model capable of simulating droplet coalescence dynamics and investigating diffusive mixing within droplets. Validation of this model against previously published experimental results and analytical test cases has been successful, and insights gained from this model have facilitated exploration of mixing at the inkjet application scale.

What did you wish you knew before starting a PhD?

As my supervisors like to remind me “research doesn’t happen day to day”. I’m definitely quite an impatient person and like immediate results but in my project simulations can take days to run (and that’s if I’ve set them off correctly!) which means you have to be patient and good at organising yourself. The fact that things take such a long time can feel as though you aren’t making progress compared to other people but everything has a way of coming together if you keep putting the work in.

What are your plans for the future?

I would really like to become a lecturer someday, but this might be a long ways off! In the short term hopefully I will be able to stay in academia and continue to research interesting things like droplet dynamics in hopes that will lead to me being able to share my passion for applied maths and fluid dynamics.