Spheroidal swimmers in viscosity gradients

Swimming microorganisms and active particles demonstrate taxis, a unique behavior that facilitates their navigation within intricate and variable environments by adjusting their orientation in response to changes in chemical or material gradients. Past research has shown that spherical active (squirmer) particles tend to reorient to swim down viscosity gradients, i.e., display negative viscotaxis. In talk, we discuss the role of shape on viscotaxis, namely we studied the hydrodynamics of prolate spheroidal squirmers in linear viscosity gradients, offering a more accurate model for non-spherical swimmers like paramecium. Our findings suggest that spheroidal squirmers, irrespective of being classified as pushers, pullers, or neutral swimmers, display behaviors analogous to those of their spherical counterparts; however, slenderness tends to diminish the impact of the viscosity gradient on the dynamics.