【摘要】 提出和优化了环形稀疏声源阵列涡旋声场的形成方法,进行了涡旋声压,相位和振动速度的理论推导和特性分析。通过改变声源数、声源频率和观测距离等参数,对声涡旋场的模拟结果证明,声涡旋半径主要由信号波长决定,声源频率越高,声涡旋半径越小,能量越集中;涡旋声压随着声源数的增加而线性提高,随着传播距离的增加而减小;声涡旋环形相位分布的线性度随着声源数、声源波长和传播距离的增加而提高。建立了3/4/6/8声源实验系统,径向声压和相位分布以及环形相位分布的测量结果和模拟结果具有较好的一致性,同时悬吊泡沫盘的旋转证明了声涡旋角动量的传输。本研究中声涡旋场的特性分析和参数优化为粒子操控及其在生物医学中的应用提供了依据。更多还原

【Abstract】 The method of the generation of acoustical vortices with annularly distributed sparse sources is proposed and it is also optimized for field manipulation.Theoretical derivations and analyses of acoustic pressure and phase as well as vibration velocity of the generated acoustical vortices are conducted.By changing the parameters of source number,frequency and transmission distance,3-D pressure distributions of acoustical vortices are simulated.It is proved that the radius of acoustical vortices is mainly determined by the wave length of the sources.The higher the frequency is,the more concentrated energy of acoustical vortices with smaller radius can be generated.It is also demonstrated that the pressure peak of acoustical vortices increases with the increase of source number,while decreases for increased propagation distance.Meanwhile,the linearity of the circular phase distribution of acoustical vortices enhances for increased source number,longer wave length and bigger transmission distance.In addition,with the experimental setup using 3/4/6/8 sources,the measured radial and circular distributions of pressure and phase agree well with the numerical results,and the rotation of the suspended foam disk also demonstrates the existence of angular momentum transfer of acoustical vortices.The favorable results of property analysis and parameter optimization for acoustical vortices provide the basis for particle manipulation in biomedical engineering.更多还原