Coordinated use of FEM/BEM and SEA for the acoustic response of Delta II RL 10B-2 deployable nozzle

1998 ◽  
Author(s):  
Mary Baker ◽  
Paul Blelloch ◽  
Tom Burton ◽  
Frederick Payne
Keyword(s):  
Acoustic Response

APPLICATION OF UNCONVENTIONAL METHODS FOR FREQUENCY ANALYSIS IN ACOUSTICS

Akustika ◽  
2020 ◽  
Vol 36 (36) ◽  
pp. 25-32
Author(s):  
Jaroslav Smutný ◽  
Dušan Janoštík ◽  
Viktor Nohál
Keyword(s):  
Fourier Transform ◽  
Discrete Fourier Transform ◽  
Frequency Analysis ◽  
Mathematical Analysis ◽  
Measured Data ◽  
Application Area ◽  
Acoustic Response ◽  
Recommendations For Practice ◽  
Unconventional Methods ◽  
Frequency Area

The goal of this study is to familiarize a wider professional public with not fully known procedures suitable for processing measured data in the frequency area. Described is the use of the so-called Multi-taper method to analyze the acoustic response. This transformation belongs to a group of nonparametric methods outgoing from discrete Fourier transform, and this study includes its mathematical analysis and description. In addition, the use of respective method in a specific application area and recommendations for practice are described.

scholarly journals Swirl–nozzle interaction experiment: quasi-steady model-based analysis

2021 ◽  
Vol 62 (8) ◽  
Author(s):  
Lionel Hirschberg ◽  
Friedrich Bake ◽  
Karsten Knobloch ◽  
Angelo Rudolphi ◽  
Sebastian Kruck ◽  
...  
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Acoustic Pressure ◽  
Quantitative Information ◽  
Acoustic Response ◽  
Flow Measurements ◽  
Flow Rate Change ◽  
Interaction Experiment ◽  
Swirl Stabilized Combustion

AbstractMeasurements of sound due to swirl–nozzle interaction are presented. In the experiment a swirl structure was generated by means of unsteady tangential injection into a steady swirl-free flow upstream from a choked convergent–divergent nozzle. Ingestion of swirl by the choked nozzle caused a mass-flow rate change, which resulted in a downstream-measured acoustic response. The downstream acoustic pressure was found to remain negative as long as the swirl is maintained and reflections from the open downstream pipe termination do not interfere. The amplitude of this initial acoustic response was found to be proportional to the square of the tangential mass-flow rate used to generate swirl. When the tangential injection valve was closed, the mass-flow rate through the nozzle increased, resulting in an increase of the downstream acoustic pressure. This increase in signal was compared to the prediction of an empirical quasi-steady model, constructed from steady-state flow measurements. As the opening time of the valve was varied, the signal due to swirl evacuation showed an initial overshoot with respect to quasi-steady behavior, after which it gradually decayed to quasi-steady behavior for tangential injection times long compared to the convection time in the pipe upstream of the nozzle. This demonstrates that the acoustic signal can be used to obtain quantitative information concerning the time dependence of the swirl in the system. This could be useful for understanding the dynamics of flow in engines with swirl-stabilized combustion. Graphic abstract

Design and optimization of local acoustic response in mid-frequency vibro-acoustic systems

2021 ◽  
Vol 181 ◽  
pp. 108177
Author(s):  
Yang Yu ◽  
Guozhong Zhao ◽  
Shanhong Ren ◽  
Yuming Li
Keyword(s):  
Acoustic Response ◽  
Design And Optimization

Acoustic response of a rigid-frame porous medium plate with a periodic set of inclusions

2009 ◽  
Vol 126 (2) ◽  
pp. 685-693 ◽  
Author(s):  
J.-P. Groby ◽  
A. Wirgin ◽  
L. De Ryck ◽  
W. Lauriks ◽  
R. P. Gilbert ◽  
...  
Keyword(s):  
Porous Medium ◽  
Acoustic Response ◽  
Rigid Frame

scholarly journals Analytical model of the acoustic response of nanogranular films adhering to a substrate

2021 ◽  
Vol 104 (3) ◽  
Author(s):  
Gianluca Rizzi ◽  
Giulio Benetti ◽  
Claudio Giannetti ◽  
Luca Gavioli ◽  
Francesco Banfi
Keyword(s):  
Analytical Model ◽  
Acoustic Response

scholarly journals Acoustic response of submarine volcanoes in the Tofua Arc and northern Lau Basin to two great earthquakes

2013 ◽  
Vol 196 (3) ◽  
pp. 1657-1675 ◽  
Author(s):  
DelWayne R. Bohnenstiehl ◽  
Robert P. Dziak ◽  
Haru Matsumoto ◽  
James A. Conder
Keyword(s):  
Acoustic Response ◽  
Lau Basin ◽  
Great Earthquakes

Synthetic reflection seismograms in three dimensions by a locked‐mode approximation

Geophysics ◽  
1989 ◽  
Vol 54 (3) ◽  
pp. 350-358 ◽  
Author(s):  
G. Nolet ◽  
R. Sleeman ◽  
V. Nijhof ◽  
B. L. N. Kennett
Keyword(s):  
Finite Difference ◽  
Born Approximation ◽  
Large Scale ◽  
Layered Medium ◽  
Three Dimensional ◽  
Simple Algorithm ◽  
Realistic Model ◽  
Three Dimensions ◽  
Acoustic Response ◽  
Many Sources

We present a simple algorithm for computing the acoustic response of a layered structure containing three‐dimensional (3-D) irregularities, using a locked‐mode approach and the Born approximation. The effects of anelasticity are incorporated by use of Rayleigh’s principle. The method is particularly attractive at somewhat larger offsets, but computations for near‐source offsets are stable as well, due to the introduction of anelastic damping. Calculations can be done on small minicomputers. The algorithm developed in this paper can be used to calculate the response of complicated models in three dimensions. It is more efficient than any other method whenever many sources are involved. The results are useful for modeling, as well as for generating test signals for data processing with realistic, model‐induced “noise.” Also, this approach provides an alternative to 2-D finite‐difference calculations that is efficient enough for application to large‐scale inverse problems. The method is illustrated by application to a simple 3-D structure in a layered medium.

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