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JET-AIRFRAME INTERACTIONS FOR NOISE SUPPRESSION

PI Reda Mankbadi

JET-AIRFRAME INTERACTIONS FOR NOISE SUPPRESSION

The Embry-Riddle team developed a passive noise suppression technology utilizing the interactions of the airframe with the jet plume. In this technology, the flat surface of the airframe adjacent to the jet plume is modified to create a slightly wavy surface instead. Such design modification can be applied to the existing design concepts with engine mounted under the wing, as well as, the top-mounted engine configurations.

The near-field perturbations are reflected by the wavy surface to create an excitation wave to amplify the jet and the shear layer instability. The wavy-surface parameters are designed such that the excitation frequency is the harmonic of the fundamental frequency responsible for the peak noise. Through nonlinear fundamental-subharmonic interaction, the sound source and its radiated far-field noise are reduced. 

To verify this concept, high-fidelity simulations of a supersonic rectangular jet in the vicinity of the airframe surface were carried out. Results show that when the flat airframe surface is reduced by a wavy one, the radiated sound was reduced by 3.7dB for top-mounted engine, and by 2.6dB  for under-airframe engine.

Implemntation of wavy surface design to suppress jet-surface interaction noise.

(Left) Top-mounted engine configuration, (Right) Conventional enginr-under airframe design

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Acoustic spectra at the far-field observer 42 diameters away from the nozzle exit

 (Left) Engine mounted on top of airframe, (Right) Engine mounted under the wing


Research Dates

08/18/2018 to 11/12/2023

Researchers

  • Reda R. Mankbadi

    Reda R. Mankbadi

    Department
    Aerospace Engineering Department
    Degrees
    Ph.D., Brown University

Categories: Faculty-Staff