Study On The Acoustic Radiation Force Of Gaussian Beam On Cylindrical Particles In Water

There is acoustic radiation force on the interface of barrier in the process of the spread of sound waves in medium. The direction of the radiation force is same with the direction of wave propagation. Acoustic radiation force has important application in real life, such as Acoustic tweezers, Ultrasonic drug delivery, Ultrasonic levitation, Ultrasonic imaging and other fields. Most studies about acoustic radiation force focused on regular particles such as spherical and cylindrical particles. As a typical target, cylindrical particle is found in many applications, so that the acoustic radiation force of cylindrical particles in water is studied at present paper, which includes rigid cylinder, elastic cylinder and viscoelastic cylinder. The main contents of the paper are presented as bellowing:(1) An arbitrarily incident Gaussian beam is expressed by finite series expansion equations of cylinder Bessel function.The incident Gaussian beam is expressed by finite series expansion equations of cylinder Bessel function, basing the acoustic wave theory and combining the feature of cylindrical particles. The translational addition theorem for Bessel functions is employed to obtain an arbitrarily incident Gaussian beam. The expansion coefficient for the off-axial Gaussian beam is deduced and the waveforms of Gaussian beam are simulated.(2) Acoustic radiation force of cylindrical particles by off-axial Gaussian beam in water is studied.The axial and transverse radiation force functions of cylindrical particles by off-axial Gaussian beam are deduced, the exact expression of acoustic radiation force of rigid cylinder, elastic cylinder and viscoelastic cylinder is calculated respectively.(3) Numerical results of acoustic radiation force are calculated for cylindrical particles of different material. The influence of offset distance, frequency and waist radius of the Gaussian beam to the acoustic radiation force is studied in detail.When frequency and waist radius are set down, the numerical results shown that the axial and transverse radiation force gradually decreases with offset distance increased, the distribution of the value of the force is on the symmetry of particle center. The axial acoustic radiation force peaks when the particle is placed at the beam center,while the transverse radiation force is zero. The direction of the axial radiation force is same with the direction of wave propagation, while the direction of the transverse radiation force turns around in some condition.When offset distance and waist radius are set down, the axial and transverse radiation force increased quickly when the frequency is small. The axial radiation force gradually tends to a stable value with the increasing of ka while the direction of the transverse radiation force turns around.When offset distance and frequency are set down, the axial radiation force increases with waist radius increased, while the transverse radiation force decreases with waist radius increased.