Simultaneous Measurements of Velocity and Fluctuating Static-Pressure in a Circular Jet

Velocity and fluctuating static-pressure were measured simultaneously in a circular jet in order to discuss the pressure transport of turbulent energy and the generation mechanism of aerodynamic sound in relation to vortical structure. A combined sensor, which consists of X-type hot-wire and pressure probe, was used for the simultaneous measurements. The air jet was issued from a sharp-edged circular orifice under the excitation at the interaction mode so that velocity and fluctuating static-pressure can be determined in space and time domains by using phase-average technique. The results suggest that the simultaneous measurements with the phase-average technique give us useful information to reveal the turbulent shear flow phenomena. In particular, the pressure transport is closely related to vortical structure, and intense sound sources are caused by the vortex merging and by the acceleration of vortices during vortex pairing.