Two-point coherence of wavepackets in turbulent jets

Resumo

© 2016 by The Authors.An experiment has been designed in order to address the questions that remain open following the experiments, analysis and modelling reported in Cavalieri et al (2013). The same Mach 0.4 turbulent jet is considered, but this time using two independent-but-synchronised, time-resolved, stereo PIV systems. Each system can be moved independently, allowing simultaneous measurement of velocity in two, axially separated, cross-flow planes, enabling eduction of the two-point coherence of wavepackets. This and the associated lengthscales are studied and compared with those of the energy containing turbulent eddies. Different scaling behaviours are observed which have important implications for jet-noise modelling.