Mechanisms and active control of jet-induced noise

Andreas Babucke (1) , Bruno Spagnoli (2) , Christophe Airiau (2) , Markus Kloker (1) , Ulrich Rist (1)

1 Institut für Aerodynamik und Gasdynamik - IAG (Stuttgart, Germany)
2 IMFT - Institut de mécanique des fluides de Toulouse

Fundamental mechanisms of jet noise are investigated by means of direct numerical simulation. In the mixing layer, subharmonics of the respective vortex pairing are found to be responsible for the main part of the generated noise which is directed in downstream direction. By modifying the phase shift between introduced disturbances it is possible to diminish or enhance relevant portions of the emitted sound. Optimal control has been applied successfully to a plane mixing layer. In the far field, the mean noise level could be reduced. Depending on the measurement line, some distributed control or anti-noise is generated by the control. A more realistic configuration is achieved by adding a splitter plate representing the nozzle end. Rectangular serrations lead to a breakdown of the large coherent spanwise vortical structures and thus provide a noise reduction of 9dB.

Mots clés: Noise control; Direct numerical simulation; Adjoint equations

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

Andreas Babucke, Bruno Spagnoli, Christophe Airiau, Markus Kloker, Ulrich Rist. Mechanisms and active control of jet-induced noise. Numerical Simulation of Turbulent Flows and Noise Generation, 2009, 104, pp.75-98. ⟨hal-03474834⟩