Microphone-Array Measurements of Acoustic and Hydrodynamic Wall-Pressure Fluctuations in a Low-Speed Cavity Flow

2004 ◽  
Author(s):  
Ihab Bassioni ◽  
Mohamed Daoud ◽  
Mostafa Abdelkhalek ◽  
Ahmed Naguib ◽  
Zakaria Ghoneim
Keyword(s):  
Microphone Array ◽  
Pressure Fluctuations ◽  
Cavity Flow ◽  
Wall Pressure ◽  
Low Speed ◽  
Wall Pressure Fluctuations ◽  
Array Measurements

Microphone-Array Measurements of the Floor Pressure in a Low-Speed Cavity Flow

AIAA Journal ◽  
2006 ◽  
Vol 44 (9) ◽  
pp. 2018-2023 ◽  
Author(s):  
Mohamed Daoud ◽  
Ahmed M. Naguib ◽  
Ihab Bassioni ◽  
Mostafa Abdelkhalek ◽  
Zakaria Ghoneim
Keyword(s):  
Microphone Array ◽  
Cavity Flow ◽  
Low Speed ◽  
Array Measurements

LES Prediction of Wall-Pressure Fluctuations and Noise of a Low-Speed Airfoil

2009 ◽  
Vol 8 (3) ◽  
pp. 177-197 ◽  
Author(s):  
Meng Wang ◽  
Stephane Moreau ◽  
Gianluca Iaccarino ◽  
Michel Roger
Keyword(s):  
Boundary Layer ◽  
Wind Tunnel ◽  
Pressure Fluctuations ◽  
Wall Pressure ◽  
Transition To Turbulence ◽  
Trailing Edge ◽  
Frequency Spectra ◽  
Potential Core ◽  
Low Speed ◽  
Wall Pressure Fluctuations

This paper discusses the prediction of wall-pressure fluctuations and noise of a low-speed flow past a thin cambered airfoil using large-eddy simulation (LES). The results are compared with experimental measurements made in an open-jet anechoic wind-tunnel at Ecole Centrale de Lyon. To account for the effect of the jet on airfoil loading, a Reynolds-averaged Navier-Stokes calculation is first conducted in the full wind-tunnel configuration, and the mean velocities from this calculation are used to define the boundary conditions for the LES in a smaller domain within the potential core of the jet. The LES flow field is characterized by an attached laminar boundary layer on the pressure side of the airfoil and a transitional and turbulent boundary layer on the suction side, in agreement with experimental observations. An analysis of the unsteady surface pressure field shows reasonable agreement with the experiment in terms of frequency spectra and spanwise coherence in the trailing-edge region. In the nose region, characterized by unsteady separation and transition to turbulence, the wall-pressure fluctuations are highly sensitive to small perturbations and thus diffcult to predict or measure with certainty. The LES, in combination with the Ffowcs Williams and Hall solution to the Lighthill equation, also predicts well the radiated trailing-edge noise. A finite-chord correction is derived and applied to the noise prediction, which is shown to improve the overall agreement with the experimental sound spectrum.

LES prediction of wall‐pressure fluctuations and noise of a low‐speed airfoil

2008 ◽  
Vol 123 (5) ◽  
pp. 3538-3538 ◽  
Author(s):  
Meng Wang ◽  
Stéphane Moreau ◽  
Gianluca Iaccarino ◽  
Michel Roger
Keyword(s):  
Pressure Fluctuations ◽  
Wall Pressure ◽  
Low Speed ◽  
Wall Pressure Fluctuations

Stochastic Estimation of the Flow Structure Downstream of a Separating/Reattaching Flow Using Wall-Pressure Array Measurements

Volume 1 ◽  
2004 ◽  
Author(s):  
Mohamed Daoud ◽  
Ahmed Naguib
Keyword(s):  
Velocity Field ◽  
Pressure Fluctuation ◽  
Microphone Array ◽  
Pressure Fluctuations ◽  
Wall Pressure ◽  
Splitter Plate ◽  
Array Measurements ◽  
Wall Pressure Fluctuation ◽  
Developing Flow ◽  
Taylor Hypothesis

This investigation examines the surface-pressure fluctuations and associated flow structures spatiotemporally in the developing flow downstream of the reattachment point of a fence-with-splitter-plate flow. Simultaneous measurements of the wall-pressure and velocity field were undertaken using a 16-microphone array, extending over the streamwise range 1.67 < x/Xr < 3.33 (where Xr is the mean reattachment length), and X-hotwire sensor at two Reynolds numbers of 8000 and 16000, based on the fence height above the splitter plate. The array data were used to obtain the wavenumber-frequency spectrum of the wall-pressure fluctuation. The results illustrate that Taylor hypothesis of frozen eddies reasonably describes the flow in the investigated zone. This allowed utilization of the time-dependent LSE of the velocity field to estimate the spatial structure of the flow above the microphone array. The results confirm the association of the most-energetic pressure fluctuation with the passage of quasi-periodic vortices.

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