Department or Program

Physics and Astronomy


t has been recently observed that there is a change in the length of day with a period of roughly six years, while a longer period in the change of length of day is attributed to action within Earth’s core, the six year period is theorized to be a product of the Earth’s dynamo generation. It is conjectured that a torsional wave with a six year periodicity, i.e. an oscillation in the azimuthal velocity of the outer core that propagates radially outward could explain the change in the length of the day via conservation of angular momentum. Previous simulations have identified torsional waves in both dynamo simulations and purely hydrodynamical simulations. Here we explore torsional waves as a purely hydrodynamical process, modeling Boussinesq fluids in arotating spherical shell, with no-slip boundary condition. The numerical simulations are doneby solving the Navier-Stokes equation sets using spherical Dedalus, a pseudo-spectral partial differential equation solver. There were no successful identification of torsional waves for the rapidly rotating parameter regime Ek ~10^{-6} and Ra ~ 10^8.

Level of Access

Open Access

First Advisor

Oishi, Jeffrey

Date of Graduation


Degree Name

Bachelor of Arts

Number of Pages


Open Access

Available to all.