Study on Non-linear dynamics of levitated droplet

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Non-linear dynamics of levitated droplet is investigated by the experiment with ultrasonic levitation apparatus and electrostatic levitation apparatus, and by the theoretical analysis and numerical analysis. As the results, followings are revealed.・New technology to measure the viscosity with the levitated droplet is developed for the viscosity range of 0.1 to 100 (Pa・s). In past it is impossible to measure the viscosity in the rage from 0.1 to 100 (Pa・s).・New measurement technologies of the three dimensional flow in a levitated droplet are developed based on the three dimensional PTV technique from the stereo image measurement of the levitated droplet.・The three dimensional PIV measurements are conducted under the normal gravity condition and micro gravity condition with parabolic flight in aircraft. Non-linear analysis theory is newly developed for the non-linear surface deformation of the levitated droplet.A three-dimensional simulation code has been developed based on the level set method, in which the Navier-Stokes equation for fluid motion was coupled with an equation for interface dynamics. The simulation code was parallelized, and numerical simulations of a rotating-oscillating liquid droplet were performed. It was shown that the frequency decreased as the amplitude increased, while the frequency increased as the rotation increased. The pressure field in the droplet was found to be closely related to the frequency shift. The effects of viscosity and surface tension on the frequency shift were made clear.