A Mathematical Model for the Interaction of Anisotropic Turbulence with Porous Surfaces
ORAL
Abstract
Leading-edge noise is a complex phenomenon that occurs when a turbulent fluid encounters a solid object and is a notable concern in various engineering applications.
This presentation explores how existing theoretical leading-edge noise models can account for porosity at the leading edge and for anisotropic flow.
The model has two key components. First, we adjust the velocity spectrum to account for the possibility of complex anisotropy ratios in the flow. Second, we adapt the fully analytical acoustic transfer function to account for different boundaries by implementing convective impedance boundary conditions when formulating the gust diffraction problem. We apply the Wiener–Hopf technique to solve the gust-diffraction problem along the semi-infinite boundary.
Each modification is inspired by leading-edge noise experimental data obtained using a series of different porous leading edges. Experimental data demonstrates the interplay between anisotropy and leading-edge modifications while achieving the characteristic
mid-frequency noise reduction expected from porous leading edges. Our model is adapted to best fit the trends of the data via a tailored impedance function, leading to good agreement with all data sets across an extended frequency range.
This presentation explores how existing theoretical leading-edge noise models can account for porosity at the leading edge and for anisotropic flow.
The model has two key components. First, we adjust the velocity spectrum to account for the possibility of complex anisotropy ratios in the flow. Second, we adapt the fully analytical acoustic transfer function to account for different boundaries by implementing convective impedance boundary conditions when formulating the gust diffraction problem. We apply the Wiener–Hopf technique to solve the gust-diffraction problem along the semi-infinite boundary.
Each modification is inspired by leading-edge noise experimental data obtained using a series of different porous leading edges. Experimental data demonstrates the interplay between anisotropy and leading-edge modifications while achieving the characteristic
mid-frequency noise reduction expected from porous leading edges. Our model is adapted to best fit the trends of the data via a tailored impedance function, leading to good agreement with all data sets across an extended frequency range.
–
Publication: A Mathematical Model for the Interaction of Anisotropic Turbulence with Porous Surfaces
submitted to JFM, currently under review.
Presenters
-
Alistair Hales
University of Cambridge
Authors
-
Alistair Hales
University of Cambridge
-
Lorna J Ayton
University of Cambridge
-
Angus Wills
University of New South Wales
-
Chaoyang Jiang
University of New South Wales
-
Charitha M De Silva
University of New South Wales
-
Danielle Moreau
University of New South Wales
-
Con Doolan
University of New South Wales