Gyrotactic Bioconvection at Pycnoclines
Alireza Karimi (University of Notre Dame), Arezoo Ardekani (University of Notre Dame)
Hydrodynamics of Swimming Microorganisms
Tue 10:45 - 12:15
Barus-Holley 191
Bioconvection is a complex biological phenomenon causing spontaneous pattern formation and self-organization in the suspensions of motile bacteria and algae. It occurs as a result of the collective behavior of up-swimming microorganisms in response to the certain types of physical stimuli. We are interested in the special case of gyrotaxis where the swimming is directed by the balance of the viscous torque arising from shear flow and the torque due to gravity acting on a bottom-heavy cell. We investigate gyrotactic bioconvection in presence of stratification arising from thermal or solutal gradients in aquatic environments. Using large-scale numerical simulations of a continuum model consisting of Navier-Stokes equations coupled with two conservation equations for the concentration of microorganisms and stratified agent, we explore different regimes of the flow by varying the boundary conditions and the determinant parameters of the system. Also, we discuss the inhibition threshold of bioconvection in light of a linear stability analysis. The result can shed light on the characteristics of double-diffusive convection engendered by active swimmers in a stratified environment.