Sedimentation of the Chaotic Helical Ribbon (PHYS 217)

In this project, a research group partner and I explored adding a temporal degree of freedom to the center of mass of a particle our research group uses routinely, in an attempt to see if we could nucleate chaotic dynamics in Stokes flow sedimentation. We found that our particle is extremely sensitive to center of mass offsets and the chaotic dynamics were present, achievable, and extremely interesting.

In simple sedimentation, our system can be described by two degrees of freedom- tilt and spin. By introducing time-dependent oscillations of the center of mass, we create a third degree of freedom due to changing gravitational torques. We explored the routes to chaos by simulating oscillating the center of mass along all three principal axes, at different frequencies, and at different amplitudes.

We analyzed the results for Lyapunov exponents, and applied these findings to our overarching researrch goal of designing particles to have specific sedimentation characteristics.