Determination of the complex acoustic scattering matrix of a right-angled duct

2013 ◽  
Vol 134 (1) ◽  
pp. 292-299 ◽  
Author(s):  
Thomas Graf ◽  
Jie Pan
Keyword(s):  
Acoustic Scattering ◽  
Scattering Matrix

scholarly journals Direct Assessment of the Acoustic Scattering Matrix of a Turbulent Swirl Combustor by Combining System Identification, Large Eddy Simulation and Analytical Approaches

2018 ◽  
Vol 141 (2) ◽  
Author(s):  
Malte Merk ◽  
Camilo Silva ◽  
Wolfgang Polifke ◽  
Renaud Gaudron ◽  
Marco Gatti ◽  
...  
Keyword(s):  
System Identification ◽  
Large Eddy Simulation ◽  
Transfer Matrix ◽  
Acoustic Scattering ◽  
Scattering Matrix ◽  
Series Data ◽  
Swirl Combustor ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Analytical Approaches

This study assesses and compares two alternative approaches to determine the acoustic scattering matrix of a premixed turbulent swirl combustor: (1) The acoustic scattering matrix coefficients are obtained directly from a compressible large eddy simulation (LES). Specifically, the incoming and outgoing characteristic waves f and g extracted from the LES are used to determine the respective transmission and reflection coefficients via System Identification (SI) techniques. (2) The flame transfer function (FTF) is identified from LES time series data of upstream velocity and heat release rate. The transfer matrix of the reactive combustor is then derived by combining the FTF with the Rankine–Hugoniot (RH) relations across a compact heat source and a transfer matrix of the cold combustor, which is deduced from a linear network model. Linear algebraic transformation of the transfer matrix consequently yields the combustor scattering matrix. In a cross-comparison study that includes comprehensive experimental data, it is shown that both approaches successfully predict the scattering matrix of the reactive turbulent swirl combustor.

Estimation of the Acoustic Scattering Matrix for a Centrifugal Pump

2002 ◽  
Author(s):  
M. J. R. Bardeleben ◽  
D. S. Weaver
Keyword(s):  
Centrifugal Pump ◽  
Acoustic Scattering ◽  
Past Research ◽  
Scattering Matrix ◽  
Transmission Matrix ◽  
Inertial Effects ◽  
Simple Modification ◽  
Pump Housing ◽  
New Form ◽  
Predicted Values

This paper presents the results of a theoretical and experimental investigation into the acoustic scattering matrix for a centrifugal pump. Background is provided which examines past research into acoustic two-port models, illustrating the benefits and laying the groundwork for the current incarnation of the scattering matrix. The results reveal that the traditional form of the transmission matrix is not adequate for predicting the parameters of the scattering matrix and a new form is suggested. With a simple modification, the predicted values successfully capture the trend in the experimental data. The presented research is still ongoing, looking to improve the model by including the compliance of the pump housing and inertial effects at the pump ports.

Acoustic scattering and inverse problem: determination of physical parameters of a multilayered structure

1991 ◽  
Vol 7 (3) ◽  
pp. 369-378 ◽  
Author(s):  
O Lenoir ◽  
J L Izbicki ◽  
P Rembert ◽  
G Maze ◽  
J Ripoche
Keyword(s):  
Inverse Problem ◽  
Acoustic Scattering ◽  
Multilayered Structure ◽  
Physical Parameters

Determination of the Nucleon-Nucleon Elastic-Scattering Matrix. V. New Results at 25 MeV

1967 ◽  
Vol 154 (5) ◽  
pp. 1549-1557 ◽  
Author(s):  
Richard A. Arndt ◽  
Malcolm H. MacGregor
Keyword(s):  
Elastic Scattering ◽  
Scattering Matrix ◽  
Nucleon Nucleon

scholarly journals WAVE PROPAGATION AND SCATTERING FOR THE RS2 BRANE COSMOLOGY MODEL

2009 ◽  
Vol 06 (04) ◽  
pp. 809-861 ◽  
Author(s):  
ALAIN BACHELOT
Keyword(s):  
Cauchy Problem ◽  
Scattering Theory ◽  
Scattering Matrix ◽  
Asymptotic Completeness ◽  
Decay Estimates ◽  
Brane Cosmology ◽  
Dispersive Waves ◽  
Wave Operators ◽  
Global Cauchy Problem

We study the wave equation for the gravitational fluctuations in the Randall–Sundrum brane cosmology model. We solve the global Cauchy problem and we establish that the solutions are the sum of a slowly decaying massless wave localized near the brane, and a superposition of massive dispersive waves. We compute the kernel of the truncated resolvent. We prove some L1-L∞, L2-L∞ decay estimates and global Lp Strichartz type inequalities. We develop the complete scattering theory: existence and asymptotic completeness of the wave operators, computation of the scattering matrix, determination of the resonances on the logarithmic Riemann surface.

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