Ellen Bartle

PhD Project

Title: Spin-Up and Spin-Down Instabilities in Cylinders

Keywords: flow instability | turbulence | rotating flows | spectral methods

My research investigates flow instabilities and transition to turbulence in impulsive spin-up and spin-down flows within cylinders. My research combines analytical modelling, high-resolution numerical simulation and experimental visualisation to understand how rotating flows evolve with Reynolds number and aspect ratio, and how boundary effects influence the development of instabilities and vortical structures. I use spectral methods and high-performance computing to solve the incompressible Navier–Stokes equations, alongside reduced-order models and experiments to validate and interpret the numerical results.

Supervisors:

• • Cédric Beaume, Mathematics
  • Nikil Kapur, Mechanical Engineering
  • Greg de Boer, Mechanical Engineering

Papers:

• • to follow

Conferences:

• • Poster: Spin Up and Spin Down Flow Instabilities in Cylinders, 2026 CDT Symposium

Impact:

Understanding the flow behaviour that occurs when a cylindrical container is suddenly rotated or stopped has applications in industrial processes where controlled mixing and particle motion are important. One example is the production of pre-filled vaccines, where particulate debris can sometimes enter a vial during manufacture. Rotating and then rapidly stopping the vial can be used to agitate settled particles, allowing them to be detected using imaging. However, the resulting flow can be complex, making it difficult to predict where particles will move and therefore where they may be detected. My research aims to improve our understanding of these transient flows and the instabilities that develop within them, which could ultimately contribute to better prediction and control of particle transport in such processes.

Connections

I am keen to connect with researchers and industry professionals working with rotating flows, flow instabilities and turbulence, particularly those interested in using fundamental fluid dynamics to understand and improve real-world processes.

Background

I completed an MMath at the University of Lincoln, where I investigated polymer flow through 3D-printing nozzles using constitutive modelling and numerical methods. I subsequently joined the CDT in Fluid Dynamics, where my integrated master's project focused on the experimental characterisation of virgin and recycled metal powders for Laser Powder Bed Fusion. During the taught Fundamentals of Fluid Dynamics component of the integrated master's, I developed an interest in flow instabilities and transition to turbulence, which ultimately led me to pursue a PhD in this area.

Previous Research Interests

My research interests lie in flow instabilities, the transition to turbulence, and related phenomena in fluid dynamics.

Why I chose the CDT in Fluid Dynamics

I chose the CDT in Fluid Dynamics because I had been keen to continue studying fluid dynamics since my third year of undergraduate study. The CDT provided an ideal opportunity to broaden and strengthen my understanding of fluid dynamics before undertaking a PhD project, while also offering a collaborative environment in which I could learn from an interdisciplinary team, industry partners and fellow students. The programme has also provided numerous opportunities to network with academics nationally and internationally and to present and discuss my work with the wider fluid dynamics community.