Qualitative dynamics of wavepackets in turbulent jets

Onofrio Semeraro (1) , François Lusseyran (1) , Luc Pastur (1) , Peter Jordan (2)

1 LIMSI - Laboratoire d'Informatique pour la Mécanique et les Sciences de l'Ingénieur
2 PPrime [Poitiers] - Institut Pprime [UPR 3346]

We analyze the temporal dynamics associated with axisymmetric coherent structures ina turbulent jet. It has long been established that turbulent jets comprise large-scale coherentstructures, now more commonly referred to as “wave packets” [Jordan and Colonius,Annu. Rev. Fluid Mech. 45, 173 (2013)]. These structures exhibit a marked spatiotemporalorganization, despite turbulence, and we aim to characterize their temporal dynamics bymeans of nonlinear statistical tools. The analysis is based on data presented Breakey et al.,in Proceedings of the 19th AIAA/CEAS Aeroacoustics Conference, AIAA Paper 2013–2083(AIAA, Reston, VA, 2013), where time series of the wave-packet signatures are extractedat different streamwise locations. The experiment runs at Ma = 0.6 and Re = 5.7 × 105.A thorough analysis is performed. Statistical tools are used to estimate the embeddingand correlation dimensions that characterize the dynamical system. Input-output transferfunctions are designed as control-oriented models; and for this special case, consistentwith other recent studies, we find that linear models can reproduce much of the convectiveinput-ouput behavior. Finally, we show how surrogate models can partially reproduce thenonlinear dynamics.

Domaines: Physique [physics]; Mécanique des fluides [physics.class-ph]

Onofrio Semeraro, François Lusseyran, Luc Pastur, Peter Jordan. Qualitative dynamics of wavepackets in turbulent jets. Physical Review Fluids, 2017, 2, 30p. ⟨10.1103/PhysRevFluids.2.094605⟩. ⟨hal-01633922⟩