  Current design constraints have encouraged the studies of aeroacoustic fields
around compressible jet flows. The present work addresses the numerical study
of unsteady turbulent jet flows as a preparation for future aeroacoustic
analyses of main engine rocket plumes. An in-house large eddy simulation tool
is used in order to reproduce high fidelity results of compressible jet flows.
The large eddy simulation formulation is written using a second order numerical
scheme for a finite difference spatial discretization. Numerical simulations of
perfectly expanded jets are performed and the results are compared to the
literature. Dynamic mode decompositions (DMD) of the jet flow, using large size
three-dimensional snapshots, are performed. Three variables are analyzed,
namely, the velocity magnitude, the vorticity magnitude and the divergence of
velocity. In particular, two frequencies are identified and they are linked to
flow structures observed in experiments performed by other authors in the
literature. The spatial shapes of the corresponding dynamic modes are also
discussed.
