Emergence of bacterial vortex explained
Researchers from Brown University and the University of Cambridge have explained for the first time how that dual-motion vortex is generated. Using computer modeling and a clever experiment, the researchers show that the fluid flow generated by all those tiny swimmers explains that strange two-way motion. So Lushi and her colleagues developed a computer simulation that included the fluid flows created when the bacteria swim. But individuals swimming along the outside of the circle created a flow in the fluid in the opposite direction from the direction they’re swimming. The experiment showed that all the bacteria were indeed attempting to swim in the same direction.