Near field acoustic solution of a rotating point source in frequency domain

Based on the frequency domain acoustic solution of moving sourcesl this paper gives an approximate acoustic solution of a rotating point source in near field,which is the superposition of the well-known far field solution and three near field modification items if the rotating radius is acoustically compact as compared with the field sound wavelength.Accordingly,the near field Green function in free space is obtained.The directionality characteristic of the sound field induced by source rotating is discussed,and influences of source position,source frequency and rotating frequency are studied in detail