Seminar "The axisymmetric turbulent wake: analysis and control by experiment and simulation".
As part of the scientific animation of the mechanics department of the LAMIH, a seminar will be held by Jonathan Morrison, Professor at Imperial College (Department of Aeronautics)
Summary:
Coherent structures observed in baseline pressure fields are extracted in the near wake using POD. The amplitude of the symmetry-breaking mode shows that the wake is not stabilized at the center. On the contrary, it meanders between two quasi-stable positions with spatial symmetry breaking. The conditional POD with the flow field close to stable equilibrium shows that the unstable vortex detachment mode is a spatial symmetry-breaking phenomenon occurring near one side of the edge instead of simultaneously on both sides. Direct comparison of laminar LSA modes with turbulent POD modes shows that unstable laminar modes persist in the turbulent wake at high Reynolds numbers. Control is provided by a pulsed jet. Under optimal forcing conditions, a base pressure recovery of 87.6% is achieved. The evolution of coherent wake structures as a function of forcing amplitude is evaluated.