Megan S. Davies Wykes


Megan S Davies Wykes

I research experimental fluid dynamics. My interests span turbulent stratified mixing and fluid-structure interactions.

Currently, I am a postdoc researcher for Managing Air for Green Inner Cities (MAGIC), examining the interaction between building ventilation systems and their surroundings, at the Department for Applied Mathematics and Theoretical Physics (DAMTP) at the University of Cambridge.

I was previously a Courant Instructor at the Applied Mathematics Laboratory, based in the Courant Institute, New York University, where I was also a Fulbright Scholar. There I investigated the interaction between a dissolving body and a buoyancy-driven flow and flow-structure interaction at the microscale.

My PhD was on turbulent stratified mixing and the Rayleigh-Taylor instability, supervised by Dr Stuart Dalziel. I did this research at DAMTP, University of Cambridge.

Contact

megan.davieswykes@cantab.net

DAMTP,
Centre for Mathematical Sciences,
Wilberforce Road,
Cambridge,
CB3 0WA,
United Kingdom

+44 (1223) 764053

Curriculum Vitae PDF


Research

Turbulent stratified mixing

Rayleigh-Taylor instability occurs at an interface between two fluids of different densities, where the dense fluid is accelerated into the less dense fluid. My research into this instability concentrated on the turbulent mixing that occurs when a Rayleigh-Taylor unstable interface is situated between two otherwise stably-stratified layers.

I have shown that high values of the mixing efficiency (more than 70%) are possible when Rayleigh-Taylor instability is confined within an otherwise stable stratification (see pdf). These results led to new insights into mixing in unstably stratified flows (see pdf).

A video of this instability can be found on YouTube.

Flow-structure interaction at the microscale

Artificial micron-scale swimmers can be created by placing metallic rods in a chemical fuel. I am interested in how these rods can be made to self-assemble and interact with their environment, to overcome diffusion and acheive directed motion.

I have shown that diffusive rods can be made to self-assemble into structures with the two fundamental types of directed motion, rotors and T-shaped swimmers (see arXiv).

Flow-structure feedback in buoyancy-driven flows

When an object dissolves in a fluid flow, the rate of dissolution is strongly affected by the flow; as the flow will vary, the rate of dissolution will not be constant on the surface. This variability will lead to a change in shape and resulting feedback between shape and flow. The aim of my research is to identify the physical principles behind this dynamic relationship.


Publications


Guiding microscale swimmers using teardrop-shaped posts,
M. S. Davies Wykes, X. Zhong, J. Tong, T. Adachi, Y. Liu, L. Ristroph, M. D. Ward, M. J. Shelley, and J. Zhang, Soft Matter (Accepted). arXiv

Dynamic self-assembly of microscale rotors and swimmers,
M. S. Davies Wykes, J. Palacci, T. Adachi, L. Ristroph, X. Zhong, M. D. Ward, J. Zhang, M. J. Shelley, Soft Matter (2016). Journal arXiv

On the meaning of mixing efficiency for buoyancy-driven mixing in stratified turbulent flows,
M. S. Davies Wykes, G. Hughes and S. B. Dalziel, Journal of Fluid Mechanics (2015), v. 781, pp. 261–275. Journal PDF

Efficient mixing in stratified flows: experimental study of a Rayleigh-Taylor unstable interface within an otherwise stable stratification,
M. S. Davies Wykes and S. B. Dalziel, Journal of Fluid Mechanics (2014), v. 756, pp. 1027-1057. Journal PDF


Efficient mixing in stratified flows: Rayleigh-Taylor instability within an otherwise stable stratification,
PhD thesis (2014). Supervisor: Dr Stuart Dalziel. PDF

Stability of a Rotating Boundary Layer,
Master's thesis (2010). Supervisor: Prof Peter Davidson. PDF


Thin casting of silicon,
For Elkem and Teknova, 91st European Study Group with Industry Bristol (2013). Report

Train positioning and track location using video odometry and track curvature,
For RDS International, 100th European Study Group with Industry Oxford (2014). Report