An experimental and numerical study on flagellar spiral motion

Microbes can move smoothly in water environment with high efficiency, which could offer innovative ideas for micro hydro machines in future. In this study, we investigated the spiral movement of flagellum by using numerical and exerimental models. We simulated a microbe's fluid environment of Re number of 10^-4. The model study revealed that the maximum values of driving force and fluid velocity appeared depending on the model's roll number and spiral diameter. The occurrence of the maximum was explained by the two competing factors, which were the increase in longitudinal velocity and the decrease of spiral wave velocity as the roll number increased.