Simultaneous far field pressure/in-flow velocity fluctuations were measured in a turbulent jet flow at low Ma number. Measurements were conducted using 2 component Laser Doppler Velocimetry technique and standard microphones. The velocity signals, acquired in several positions within the flow field, were conditioned on the far field pressure peaks and signatures of ensemble averaged noise emitting events were retrieved. The results reported here definitely confirm previous outcomes obtained on the same apparatus showing that intermittent structures generated within the turbulent region of the jet, i.e. around 10 diameters downstream the jet exit, give a relevant contribution to the overall far field noise.
展开▼
