LIFD Early Career Researcher Spotlight: Ellen Bartle

Thesis Title:

Spin-up and Spin-down Flow Instabilities in Rotating Cylinders

School/Faculty:

School of Computer Science

Supervisors:

Dr Cédric Beaume, Prof Nik Kapur, Dr Greg de Boer

Tell us a bit about yourself:

I’m currently in the second year of the Fluid Dynamics CDT programme and in the first year of my PhD. Previously, I completed an integrated Master’s in Mathematics at the University of Lincoln, where I first discovered my passion for fluid dynamics. I decided to apply to the CDT to continue deepening my understanding of fluid dynamics while also developing the broader skills needed to collaborate and conduct research alongside others with similar interests. Outside of the CDT, I enjoy botany, cooking and baking, and rock climbing.

What is your research about?:

My research investigates the transient fluid dynamics that arise of Newtonian fluids in bounded rotating cylinders. Despite their geometric simplicity, these flows exhibit complex behaviours driven by viscous boundary layers, angular momentum redistribution, and flow instabilities. By combining analytical solutions of the Navier–Stokes equations under axisymmetric assumptions with high-resolution spectral numerical simulations, I aim to characterises the development and spatial structure of vortical instabilities. Then I will conduct a parametric analysis to explore how the aspect ratio influences the flow, demonstrating convergence toward unbounded behaviour as the cylinder aspect ratio changes. These findings will contribute critical insights into the onset and evolution of instabilities in confined rotating flows, which are relevant to a range of applications from projectile dynamics to food and pharmaceutical processing.

What did you wish you knew before starting a PhD?:

Pursuing a PhD has taught me that research progress is often slower than anticipated. This realisation pushed me to develop resilience and patience, especially when extensive effort led to inconclusive or negative results. Over time, I learned to value small milestones and view setbacks as opportunities for growth rather than failures. I also came to understand that succeeding in a PhD involves more than academic performance, it requires initiative in seeking out professional development opportunities and a thoughtful approach to career planning beyond academia. Equally important has been maintaining a healthy work-life balance. While deadlines sometimes demand long hours, establishing a structured routine has been essential for sustaining my mental well-being. If I could offer my earlier self one piece of advice, it would be to embrace uncertainty. By remaining adaptable and open to change, I’ve found the PhD journey not only manageable but genuinely fulfilling, shaped as much by its challenges as by its discoveries.

What are your plans for the future?

I have greatly enjoyed the style of research I’ve pursued during my PhD, particularly in fluid dynamics, and this has shaped my intention to continue along the academic path through a postdoctoral position. I’m motivated by the opportunity to apply the expertise I’ve developed while also being challenged to grow intellectually and technically. At the same time, I remain open to roles in both academia and industry, especially those that emphasize research and development. Whether as a postdoc or in a research and development setting, I’m seeking opportunities that allow me to contribute meaningfully while continuing to expand my skills and explore new directions in fluid mechanics