Acoustic Manipulation Of Particles By Asymmetrically Structured Artificial Plate

In recent years,the studies on acoustic radiation forces are gradually transferring to acoustic forces by acoustic artificial structures.Compared to traditional methods,there are many advantages by employing acoustic artificial structures to manipulate particles:e.g.the frequency for acoustic trapping can be arbitrarily designed by tuning the lattice constant,also the localized fields to manipulate particles can be designed by tuning the artificial structures.Currently,most of acoustic artificial structures on manipulation of particles are focused on symmetrical structures of one-dimensional or two-dimensional acoustic periodic structures.In this dissertation,we extended the studies to asymmetrical and three-dimensional acoustic structures.We believe that our studies can push some development of acoustic manipulation,enrich the methods of controlling particles by acoustic waves and enhance the understanding of acoustic manipulation.Our main works are included as follows:Firstly,based on three-dimensional acoustic structured plates,we studied the acoustic radiation forces on three-dimensional brass particles.We demonstrated that the acoustic trapping is originated from the resonant excitation of acoustic surface waves in the plate.Further,we studied the effects of particle size and location on acoustic trapping.It elucidated that the acoustic trapping is near field.Second,we studied the acoustic radiation forces by the excitation of acoustic surface waves in two-dimensional structured plates with periodic grooves.The results demonstrated that in the whole frequency range with acoustic surface waves,the acoustic radiation forces on particle are negative,which is interesting on wide-frequency manipulation.By introducing graded grooves on the system,the acoustic particle can be controlled to move towards to the source,which can be exploited for the transportation of acoustic particles.At last,we studied the effects of acoustic cavity in two-dimensional sonic crystal on acoustic radiation forces.We designed a fan-shaped hybrid structures with different cavities,it demonstrated that the particle can be pushed out to different direction by tuning the resonant frequency,which may be useful on sorting particles.