Sound Pressure Fields Focused Using Biconcave Acoustic Lens for Normal Incidence

2004 ◽  
Vol 43 (5B) ◽  
pp. 3163-3168 ◽  
Author(s):  
Toshiaki Nakamura ◽  
Yuji Sato ◽  
Tomoo Kamakura ◽  
Tetsuo Anada
Keyword(s):  
Sound Pressure ◽  
Normal Incidence ◽  
Acoustic Lens ◽  
Pressure Fields

scholarly journals Dense U-Net for Limited Angle Tomography of Sound Pressure Fields

2021 ◽  
Vol 11 (10) ◽  
pp. 4570
Author(s):  
Oliver Rothkamm ◽  
Johannes Gürtler ◽  
Jürgen Czarske ◽  
Robert Kuschmierz
Keyword(s):  
Measurement Errors ◽  
Sound Pressure ◽  
Tomographic Reconstruction ◽  
Synthetic Data ◽  
Projection Data ◽  
Quantitative Measurements ◽  
Pressure Fields ◽  
The Neural Network ◽  
Bias Flow ◽  
3D Information

Tomographic reconstruction allows for the recovery of 3D information from 2D projection data. This commonly requires a full angular scan of the specimen. Angular restrictions that exist, especially in technical processes, result in reconstruction artifacts and unknown systematic measurement errors. We investigate the use of neural networks for extrapolating the missing projection data from holographic sound pressure measurements. A bias flow liner was studied for active sound dampening in aviation. We employed a dense U-Net trained on synthetic data and compared reconstructions of simulated and measured data with and without extrapolation. In both cases, the neural network based approach decreases the mean and maximum measurement deviations by a factor of two. These findings can enable quantitative measurements in other applications suffering from limited angular access as well.

Experimental synthesis of sound pressure fields for active structural acoustic control testing

2013 ◽  
Vol 25 (7) ◽  
pp. 881-889 ◽  
Author(s):  
Stephan Algermissen ◽  
Sebastian Meyer ◽  
Christina Appel ◽  
Hans P Monner
Keyword(s):  
Sound Pressure ◽  
Pressure Fields ◽  
Acoustic Control ◽  
Structural Acoustic Control

Force Distribution Dependence of Sound Radiation From a Doubly Rib-Stiffened Plate

1999 ◽  
Author(s):  
David Feit ◽  
Daniel DiPerna
Keyword(s):  
Sound Pressure ◽  
Single Point ◽  
Force Distribution ◽  
Velocity Spectrum ◽  
Far Field ◽  
Pressure Fields ◽  
Coherent Interaction ◽  
Line Force ◽  
Reaction Forces ◽  
Analytical Formulae

Abstract Analytical formulae for both the velocity spectrum and the acoustic far-field radiated sound pressure for a doubly rib-stiffened (small frames and bulkheads) fluid-loaded elastic plate, excited by several different force distributions, are derived. The force distributions are (1) a line-force applied at a single point and (2) two Gaussian distributed force intensities whose effective width either spans the small rib spacing or the large rib spacing. The far-field sound pressure as a function of frequency is calculated. The concentrated line force case shows evidence of frame interference effects (sometimes referred to as Bloch waves) in the radiated pressure fields. These arise from coherent interaction of the pressure fields emanating from the frame reaction forces and the applied force pressure field. The frequencies at which these coherence effects are manifest depend on the stiffeners’ spacing as compared to the fluid-loaded flexural wavelength. The Gaussian force distribution eliminates these interaction effects depending on whether or not the effective force width is greater or less than the respective rib spacing.

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