Optimum Design of Wiggling Micromachine with respect to Thrust Generation

Abstract

We investigate the behavior of vortex patterns and hydrodynamic forces of a wiggling machine in order to find optimum design standard with respect to thrust generation; the wiggling machine is moving in Reynolds number ranging from 10 to 200. Dimensionless amplitude and wavelength are manipulated to obtain the highest propulsive performance. In general, smooth design such as fish-like body shape has the most efficient performance for generating thrust; however it differs according to both Reynolds number and dimensionless amplitude and wavelength. Namely, increment of the viscous effect on the micromachine body and restriction of its rear edge amplitude inhibits the wiggling motion. Therefore, flexible motion should be applied toward micromachine. We present two equations as a function of wavelength, amplitude, St, and Re, and these directly aid development of a micromachine which could travels inside blood vessel with low Reynolds number flow region.