Research on characteristics of the sound field on the velocity hydrophone

On the basis of the principle of measuring particle velocity using velocity hydrophone with co-oscillating sphere in the underwater sound field, we derived mathematical expressions of sound pressure presented for the velocity hydrophone. The characteristics of the velocity field and the sound pressure field on the surface of the velocity hydrophone were computed and analyzed. The results show that density ratio M/m affects the upper limit of the work frequency and velocity sensitivity of the velocity hydrophone,which decrease with the increasing density ratio M/m.The effect of velocity hydrophone has on the surrounding sound pressure hydrophone was also computed.The results show that density ratio M/m has great effects on sound pressure that was measured by sound pressure hydrophone in front of and behind the velocity hydrophone,but sound pressure is related with the direction of the incident wave in the range of ka≥0.5.