Research On The Acoustic Radiation Force Of Plane Wave Obliquely Incident On Elastic Cylindrical Particles

Acoustic radiation force is a kind of nonlinear phenomenon produced by the interaction between scattering particles and acoustic wave.Particles can be captured and controlled through using acoustic radiation forces(ARF).Therefore,the research on the acoustic radiation force of particles is the core of non-contact particle manipulation technology.Along With the in-depth development of relevant research,the organic combination of acoustic non-contact micro-manipulation technology and other technologies has produced a lot of new research methods and research fields,so that it effectively promoted the cross research and development in the fields of biology science,physics,materials science,medicine and nanotechnology.However,in the current research work of acoustic radiation force,the main research is the acoustic radiation force of the sound wave normal incidence to the infinite long cyhndrical particles.In the actual environment,situation of the oblique incidence sound waves into the finite long cylindrical particles is commoner and more complex.If taking into consideration of the influence of sound wave incidence angle and particle length on acoustic radiation force,it is of reference value for efficient and flexible manipulation of cylindrical particles with acoustic radiation force.There is little research on the acoustic radiation force of a finite cylindrical particle with oblique incidence.We derived a analytical formula for calculating acoustic radiation force on elastic cylindrical particles in obliquely incident acoustic waves based on acoustic scattering theory.The research content and innovation points includes the following aspects:1.The scattering coefficients of infinite cylindrical partieles and finite cylindrieal particles incident by the plane acoustic wave at arbitrary angles are derived and given,which laid the foundation of the acoustic radiation forces.2.We derived an expression for calculating the acoustic radiation force function of an infinite cylindrical particle in an obliquely-incident plane wave sound fields and investigate the influence of materials of elastic cylindrical particles and incident angles on the acoustic radiation force.It is found that new resonance modes appear in elastic cylinders with different materials,when the incident angle changes from normal incidence to oblique incidence.That is responsible for the increase of resonance peaks on Yp-ka curves for aluminium and stainless steel cylinder and the enhancement of resonance peaks on the curves of gold and lead cylinders.When the incident angle closes to the critical ancle of longitudinal wave,the resonance peaks on the Y,-ka curve of elastic cylinder(except beryllium)decrease.When the incident angle is near the critical angle of the fluid wave resonance,a fluid resonance peak appears on the Yp-ka curve of the elastic column(except beryllium)at a small ka.When the incident angle is nearby the critical angle of shear wave,the resonance peaks on the Yp-ka curves reduce farther and the amplitude is smaller.3.Using the method of stationary phase,derive the expression of acoustic radiation force function of cylindrical particles with finite length incident at any angle of plane wave under the condition of the finite length cylinder is a part of an infinitely long straight cylinder with the same radius and the scattering sound field of the near field is the same as the scattering sound field of infinite length cylinder.The effects of incident angle and cylinder length on the acoustic radiation force of cylindrical particles were analyzed.There is no obvious distincting on the Yp-ka curves of rigid cylinder and beryllium cylinder at small incidence angle of acoustic wave on the cylindrical particle.The acoustic radiation force of rigid cylinder is proportional to the length of the cylindrical particle.When acoustic wave incident on elastic cylinder(except beryllium)at small angle,the new peaks and original peaks move towards the high frequency region with the increasing incident angle.,its Yp curve strengthen.The amplitude of the Yp-ka curve of elastic cylinder(except betyllium)decreases When the acoustic wave incident on elastic cylinder at the critical angle of longitudinal wave.The amplitude of the Yp-ka curve of elastic cylinder(except beryllium)becomes smaller and its resonance peaks decreases when the acoustic wave is incident on elastic cylinder at the critical angle of the longitudinal wave.The amplitude of the Yp-ka curve of elastic cylinder is further reduced when acoustic wave is incident on cylindrical particle at the critical angle of transverse wave.The amplitude of acoustic radiation force function of elastic cylinder increases with the length of cylindrical particle increase.4.The three-dimensional finite element models of the plane wave oblique incidence of infinite length cylindrical particle and finite length cylindrical particle in water are respectively established through the finite element simulation soffware COMSOL.In addition,Acoustic radiation force function Yp curves versus ka for infinite length cylinder and finite length cylinder with oblique incidence of plane wave are computed and analyzed.Besides,the influence of the cylinder length on acoustic radiation force of finite lenglh cylinder was studied.According to the results,the Yp-ka curve of the infinite length cylindrical particles calculated by theory are basically consistent with the results of finite element simulation when the incidence angle is small.With the increase of the incident angle,there are some discrepancies between two results about the acoustic radiation force the infinite length cylinder got by the theoretical calculation and the finite element simulation.The mainly reason is that the finite column approximation is regarded as infinite cylinder by setting the boundary condition for the simulation calculation,when the acoustic radiation force of the particle is simulated by the finite element simulates,there by exerting an influence on the results by the end effect of the columns.For a finite length cylinder,when the length of the cylinder is L=10a and the incident angle are small,Yp-ka curves of the finite-length cylindrical particle got by the theoretically calculated and the finite element simulation have the same tendency,but the value of the result of the finite cylinder of acoustic radiation force by theoreticalcalculation is four times the value of the finite element simulation result.As the incident angle increases,the error between the results about the acoustic radiation force of the finite-length cylindrical partieles got by the theoretical calculation and the finite element simulation increase.When the incident angles are the same and the values of ka are different,the directions of acoustic radiation acting on the finite length elastic cylinder is different.