Abstract:

The coherence functions of a spherical sound wave after passing through a turbulent jet were measured for different values of sound frequencies and mean speed of the jet [Ph. Blanc-Benon, Ext. Rev. Cethedec-Ondes Signal, No. 79-1984 (1984)]. In the presentation, the experimental data obtained are compared with the theoretical predictions based on the previous theories of sound propagation in turbulent media with medium velocity fluctuations [e.g., E. H. Brown and F. F. Hall, Rev. Geophys. Space Phys. 16 (1), 47--110 (1978)] and with the predictions of the theory recently developed [V. E. Ostashev, Waves Random Media 4, 403--428 (1994)]. The differences between these theories and their results for the coherence function of a spherical wave are explained. It is also shown that the predictions based on the previous theories do not agree with the experimental data. On the other hand, the predictions of the theory developed by V. Ostashev fit the measured coherence functions fairly well. [This material is based upon work supported in part by the U.S. Army Research Office under Contract No. DAAH04-95-1-0593.]