| Summary: | 碩士 === 國立臺灣大學 === 應用力學研究所 === 102 === In recent years, research of active particles has been widely developed , but most of research is focus on the motion of single particle in bulk solution, we hope we can improve applications of active particles by observing the motion of particles on two dimensional film.
In this experiment, we construct a two-dimensional flow model. We use square soap film with different sizes, put both 3μm PS (polystyrene) particles and 3μm PS-Pt Janus particles into the soap film and inject energy into the system by different ways (including different hydrogen peroxide concentration and laser power). We use the PIV (Particle image velocimetry ) method to calculated the flow field .Hope we can establish a relation between macroscale and microscale behavior of Janus particles.
For Janus particles in hydrogen peroxide soap film, the average velocity magnitude of the active flow are more higher than passive flow, the pattern of active flow will change from irregular to regular. We try to find a possible explanation from observe the motion of single Janus particles on the soap film, and we found that the fluctuation of Janus particles son soap film is much bigger than the fluctuation in bulk solution, and the fluctuation will cause the collective motion of Janus particles. We also calculate the power spectra compare with the inverse-cascade theory , and inverse-cascade spectra has be found in some situation which satisfy the k^(-5/3) law.
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