A harmonic point source of sound was placed within the potential core of an air jet and the distortion of its sound field by the jet flow was measured. An axial intensity minimum was observed that increases with increasing velocity, frequency, or temperature. The investigation indicates that the cleft in the heart-shaded directivity pattern of subsonic jet noise can be attributed mainly to refraction.
No takes yet. Share an insight, caveat, or question.
Atvars et al. (1965) studied this question.