|Title:||Analysis on the propulsion of the acoustically actuated artificial micro-swimmer|
|Advisors:||Ruan, Haihui (ME)|
|Subject:||Hong Kong Polytechnic University -- Dissertations|
|Department:||Faculty of Engineering|
|Pages:||xii, 75 pages : color illustrations|
|Abstract:||Although people have fantasized about possibilities of nanotechnology for more than a century, the actuation and manipulation of micro-scaled robots have not been realized until the recent decade. The targeted application in the human body has excluded most of the propulsion strategies, such as the chemical and electrical actuation, and brought our attention to sonic and magnetic ones. Nevertheless, ultrasound is more conveniently applied in a medical treatment owing to its versatility and cost-effectiveness. However, a more predictable driving mechanism behind the locomotion of sound-assisted movement, also known as acoustophoresis, is imperative to be proposed. We resort to the theory of microorganism swimming herein to achieve a quantitative model of the artificial sperm-like micro-swimmer. The objective of this thesis is to investigate an efficient theoretical method to calculate the speed of advance of an acoustically actuated artificial micro-swimmer. It is composed of an ellipsoidal head and a flagellum-like tail with the length of hundreds of microns. First, we take the head of the swimmer as the clamped-end boundary conditions in terms of parameters including the sound pressure and frequency by numerical simulations. Then the equations of motion for the flagellum are derived. More specifically, to take the material damping into account, the flagellum is regarded as a Euler-Bernoulli viscoelastic beam, and the employment of the resistive force theory reaches the terminal velocity with the assistance of Galerkin method. Lastly, the influences of different parameters we focus on are investigated, including the resonance index, sperm number, and the material damping. The effects of the variable cross-section of the flagellum are studied, and a comparison with the experimental results and analytical solutions reveal that this mechanical model is qualitatively in line with expectations.|
|Rights:||All rights reserved|
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