Flow characteristics of the outer part of a circular jet with and without excitation

Statistics of flow reversal in the outer region of the near field of a circular jet are examined with and without acoustic excitation. These statistics, which include the mean duration and frequency of flow reversal, are obtained with a hot-wire/cold-wire arrangement, designed so that the cold wire senses the thermal wake of the hot-wire. The organisational influence of excitation on the large structure is largest near the nozzle but weakens with distance downstream. At ten diameters from the nozzle, the velocity structure parameters of the turbulence are unaffected by the excitation.