Aerospace Defense

Experimental investigation of the Effect of finlets height on Turbulent boundary layer Trailing-Edge Noise

Document Type : Original Article

Authors

Abbas Afshari 1
Jaber Ragani Lamouki 2

1 Department of Aerospace Engineering, Shahid Sattari Aeronautical University of Science and Technology, Tehran, Iran

2 P h.D student/Department of Mechanical Engineering, Ferdowsi University of Mashhad

Abstract
This study experimentally investigates the effect of finlet height as a passive method for trailing edge noise control. The surface pressure spectra, spanwise length scale, and eddy convection velocity in the trailing edge region are key parameters governing far-field trailing edge noise. A flat plate instrumented with unsteady pressure sensors was employed to measure these parameters. Results indicated that a region with an inverse pressure gradient was created downstream of the finlets, and this effect intensified with an increase in height. It was also determined that the height of the finlet serves as an appropriate length scale for normalizing the longitudinal position. The presence of all coarse finlets significantly reduces the surface pressure spectra across the entire frequency range, and this reduction becomes more pronounced with increasing height. Fine finlets reduced high-frequency surface pressure spectra while increasing spectral levels at low-to-mid frequencies. The use of both types of finlets has led to an increase in the length scale at mid and particularly low frequencies. The eddy convection velocity has also decreased downstream of all the coarse and fine finlets, and an increase in the height of the finlets results in a further reduction in this velocity.

Keywords

Finlet
Trailing Edge Noise
length scale
Eddy Convection Velocity

Subjects

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Aerospace Defense
Volume 3, Issue 3
Autumn 2024
Pages 90-115

  • Receive Date 17 August 2024
  • Revise Date 28 October 2025
  • Accept Date 11 December 2024

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