A discrete adjoint framework for trailing-edge noise minimization via porous material

2018 ◽  
Vol 172 ◽  
pp. 97-108 ◽  
Author(s):  
Beckett Y. Zhou ◽  
Seong Ryong Koh ◽  
Nicolas R. Gauger ◽  
Matthias Meinke ◽  
Wolfgang Schöder
Keyword(s):  
Porous Material ◽  
Trailing Edge ◽  
Trailing Edge Noise ◽  
Discrete Adjoint

scholarly journals Self Noise Reduction and Aerodynamics of Airfoils With Porous Trailing Edges

Acoustics ◽  
2019 ◽  
Vol 1 (2) ◽  
pp. 393-409 ◽  
Author(s):  
Thomas Fritz Geyer ◽  
Ennes Sarradj
Keyword(s):  
Porous Material ◽  
Porous Materials ◽  
Microphone Array ◽  
Aerodynamic Performance ◽  
Aerodynamic Noise ◽  
Trailing Edge ◽  
Suitable Material ◽  
Trailing Edge Noise ◽  
Negative Effect ◽  
Noticeable Reduction

The application of open-porous materials is a possible method to effectively reduce the aerodynamic noise of an airfoil. However, the porous consistency may have a negative effect on the aerodynamic performance of the airfoil, since very often the lift is decreased while the drag increases. In a recent investigation, the generation of trailing edge noise of a set of airfoil models made from different porous materials was examined experimentally. The materials were characterized mainly by their airflow resistivity. Besides the material, the chordwise extent of the porous material was varied, which was done by covering the front part of the porous airfoil with a thin, impermeable adhesive foil. Acoustic measurements were performed in an open jet wind tunnel using microphone array technology, while the aerodynamic performance was measured simultaneously using a six-component balance. In general, both the airflow resistivity and the extent of the porous material have an influence on the trailing edge noise. However, if a suitable material is chosen, the results show that a noticeable reduction of trailing edge noise is possible even with only a small chordwise extent of the porous material.

Adjoint-based Trailing-Edge Noise Minimization using Porous Material

2014 ◽  
Author(s):  
Beckett Yx Zhou ◽  
Nicolas R. Gauger ◽  
Seong Ryong Koh ◽  
Matthias H. Meinke ◽  
Wolfgang Schroeder
Keyword(s):  
Porous Material ◽  
Trailing Edge ◽  
Trailing Edge Noise

A Discrete Adjoint Framework for Trailing-Edge Turbulence Control and Noise Minimization via Porous Material

2016 ◽  
Author(s):  
Beckett Yx Zhou ◽  
Nicolas R. Gauger ◽  
Seong R. Koh ◽  
Matthias H. Meinke ◽  
Wolfgang Schroeder
Keyword(s):  
Porous Material ◽  
Trailing Edge ◽  
Turbulence Control ◽  
Discrete Adjoint

Computation of trailing-edge noise due to turbulent flow over an airfoil

AIAA Journal ◽  
2002 ◽  
Vol 40 ◽  
pp. 2206-2216 ◽  
Author(s):  
A. Oberai ◽  
F. Roknaldin ◽  
T. J. R. Hughes
Keyword(s):  
Turbulent Flow ◽  
Trailing Edge ◽  
Trailing Edge Noise

Noise source location and scaling of subsonic upper-surface blowing

2020 ◽  
Vol 19 (3-5) ◽  
pp. 191-206
Author(s):  
Trae L Jennette ◽  
Krish K Ahuja
Keyword(s):  
Strouhal Number ◽  
Noise Source ◽  
Low Frequency ◽  
Directivity Pattern ◽  
Source Location ◽  
Dipole Source ◽  
Frequency Noise ◽  
Noise Sources ◽  
Trailing Edge ◽  
Trailing Edge Noise

This paper deals with the topic of upper surface blowing noise. Using a model-scale rectangular nozzle of an aspect ratio of 10 and a sharp trailing edge, detailed noise contours were acquired with and without a subsonic jet blowing over a flat surface to determine the noise source location as a function of frequency. Additionally, velocity scaling of the upper surface blowing noise was carried out. It was found that the upper surface blowing increases the noise significantly. This is a result of both the trailing edge noise and turbulence downstream of the trailing edge, referred to as wake noise in the paper. It was found that low-frequency noise with a peak Strouhal number of 0.02 originates from the trailing edge whereas the high-frequency noise with the peak in the vicinity of Strouhal number of 0.2 originates near the nozzle exit. Low frequency (low Strouhal number) follows a velocity scaling corresponding to a dipole source where as the high Strouhal numbers as quadrupole sources. The culmination of these two effects is a cardioid-shaped directivity pattern. On the shielded side, the most dominant noise sources were at the trailing edge and in the near wake. The trailing edge mounting geometry also created anomalous acoustic diffraction indicating that not only is the geometry of the edge itself important, but also all geometry near the trailing edge.

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