Numerical Analysis of Bioconvection Generated by Chemotactic Bacteria in a Deep Chamber

The present study performed numerical simulations of bioconvection generated by chemotactic bacteria in a deep chamber, and clarified influences of Rayleigh number on the bioconvection and transport characteristics. The discrepancy from concentrations of oxygen and bacteria in stationary fluid appears with an increase of the Rayleigh number. At the critical Rayleigh number, a plume is generated in the center of the chamber because the bacteria near the free surface fall, and thus the bioconvection is formed. At the high Rayleigh number, the convective transport becomes dominant due to the generation of the bioconvection. The bacteria are inactive near the bottom of the deep chamber because the oxygen is not fully supplied by the diffusive and convective transports from the free surface. The oxygen consumption rate of the bacteria in the chamber is constant by the critical Rayleigh number and decreases with an increase of the Rayleigh number.