- Senior Research Software Engineer
- University of Birmingham
- Faculty profile link
- PhD Project Title
- A slurry model of the F-layer in the Earth's core
My greatest passion has always been mathematics and I graduated with first class honours from Leeds University with a BSc, MMath Mathematics degree in 2013. During my time at university, I developed an attraction to solving problems using applied mathematics, sparking my interest in fluid dynamics. Afterwards, I worked as a data analyst for a holiday comparison website before returning to academia in September 2014.
I am interested in the fluid dynamics of the Earth's deep interior. My PhD project was focused on explaining the existence of a stably-stratified layer situated at the base of the Earth's outer core, also known as the 'F-layer'. I developed a slurry theory that describes how light element released from a freezing inner core can pass through the stratified layer. This iron snow regime can also describe the cores of other satellites, such as Ganymede. By studying crystallisation in slurries, we can gain insight into other important planetary events such as the crystallisation of magma oceans.
Seismic observations suggest that a stably-stratified layer, known as the F-layer, 150–300 km thick exists at the bottom of Earth’s liquid outer core. These observations contrast with the density inferred from the Preliminary Reference Earth Model (PREM), which assumes an outer core that is well-mixed and adiabatic throughout. The liquid core is composed primarily of iron alloyed with a light component. A thermal boundary layer produces the opposite effect on the density profile compared with the observations, and single phase, thermochemical models do not provide a sufficient dynamical description of how light element is transported across the F–layer into the overlying liquid outer core. We therefore propose that the layer can be explained by a slurry on the liquidus, whereby solid particles of iron crystallise from the liquid alloy throughout the layer. The slurry model provides a dynamical explanation of how light element can be transported across a stable layer.
Why I chose the CDT in Fluid Dynamics
The reason for choosing the CDT in Fluid Dynamics is that it offered the unique opportunity of studying for my research degree in a truly multidisciplinary environment. My personal goal was to complement my strong mathematical background with a breadth of practical research skills. Regular contact with members of my cohort and academics from different backgrounds has undoubtedly enriched my knowledge of fluid dynamics in a way beyond my experience at undergraduate level.
Hardy, C.M., Wong, J. (2019). Stably stratified layers within Earth's core. Astronomy and Geophysics, 60(3), 30-35.
Wong, J., Davies, C. J. & Jones, C. A. (2018). A Boussinesq slurry model of the F-layer at the base of Earth's outer core. Geophysical Journal International, 214(3), 2236-2249. DOI link to read the paper.
Greiciunas, E., Wong, J., Gorbatenko, I., Hall, J., Wilson, M. C. T., Kapur, N., Harlen, O. G., Vadillo, D. & Threlfall-Holmes, P. (2017). Design and operation of a Rayleigh Ohnesorge jetting extensional rheometer (ROJER) to study extensional properties of low viscosity polymer solutions. Journal of Rheology, 61(3), 467-476. DOI link to read the paper.
EPSRC CDT in Fluid Dynamics 2019 Prizes - Best Paper Prize 2019 for cohort 1