Settling dynamics of flexible Brownian filaments

We investigate the settling dynamics of flexible Brownian filaments by analyzing a wide range of Peclet numbers. Using the Brownian Dynamics method, we simulate the dynamics of a single filament over a long period to take statistical measurements of the effective settling velocity and diffusion perpendicular to gravity. We observe that the competition between gravitational and thermal effects can either increase or decrease the settling velocity of the filaments, depending on their flexibility. At highly flexible regimes, we identify gravitational induced compaction of the structure leading to faster sedimentation. Also, the system shows interesting stretching and compacting non-periodic dynamics in which one of the ends is pulled out of and pulled into the compact structure. Contrastingly, for semi-flexible filaments, the compact structures are not observed. Nonetheless, the interplay between elastic, gravitational, and thermal forces leads to important secondary influences on the filament diffusion perpendicular to gravity.