Acoustic wave propagation in a toroidal waveguide carrying a mean flow

2019 ◽  
Vol 145 (3) ◽  
pp. 1902-1902
Author(s):  
Charles Thompson ◽  
Sarah Kamal ◽  
Zaineb Abdulmagid ◽  
Eyobel Haile ◽  
Samusha Najjuuko ◽  
...  
Keyword(s):  
Wave Propagation ◽  
Acoustic Wave ◽  
Mean Flow ◽  
Acoustic Wave Propagation

Acoustic wave propagation and reciprocity in a toroidal waveguide carrying a mean flow

2020 ◽  
Vol 148 (4) ◽  
pp. 2806-2806
Author(s):  
Charles Thompson ◽  
Sarah Kamal ◽  
Lejun Hu ◽  
Kavitha Chandra
Keyword(s):  
Wave Propagation ◽  
Acoustic Wave ◽  
Mean Flow ◽  
Acoustic Wave Propagation

An Extension of the Low Reduced Frequency Model for Viscothermal Acoustic Propagation Within Waveguides

2012 ◽  
Author(s):  
Clément Sambuc ◽  
Gregory Lielens ◽  
Jean-Pierre Coyette
Keyword(s):  
Wave Propagation ◽  
Acoustic Wave ◽  
Fluid Model ◽  
Heat Conducting ◽  
Mean Flow ◽  
Acoustic Wave Propagation ◽  
Cross Sectional ◽  
Frequency Model ◽  
Reduced Frequency ◽  
Automotive Catalytic Converters

Inside micro cavities, specific dissipative mechanisms influencing acoustic wave propagation occur due to viscous and heat-conducting nature of the fluid. This work focuses on a possible extension of the so called “Low Reduced Frequency” model for acoustic wave propagation in a thermoviscous fluid. This extension is built starting from geometrical and physical assumptions (boundary layer theory, straight waveguides) and consists in the incorporation of a stationary laminar and subsonic mean flow. The resulting equivalent fluid model provides a new damping coefficient which depends on the Mach number, the shear and thermal wave numbers and the cross-sectional profiles of axial velocity and temperature. The main application area is the study of acoustic attenuation within automotive catalytic converters or also thin fluid layers like cooling systems in small electronic devices. This formulation has been implemented for a simple one dimensional thin tube. Convergence to the original model in the absence of mean flow has been reached and comparisons with variational solutions given by Peat show good agreements.

scholarly journals Surge Model: Predicting Damping and Excitation Frequencies of Complex Pumping Systems

1989 ◽  
Author(s):  
Alexander Lifson ◽  
Cecil R. Sparks
Keyword(s):  
Experimental Data ◽  
Wave Propagation ◽  
Acoustic Wave ◽  
Frequency Domain Analysis ◽  
Mode Shapes ◽  
Mean Flow ◽  
Acoustic Wave Propagation ◽  
Pressure Losses ◽  
Operating Points ◽  
Interactive Dynamic

Frequency domain analysis is presented to define susceptibility of complex pumping systems to surge oscillations. In the analysis, piping spans are considered as distributed elements, compressors or pumps, orifices, valves, and junctions as lumped acoustic four pole elements. The piping elements are connected into one network through the use of appropriate matching boundary conditions. The analysis is most readily applicable to single stage units, typical of gas transmission stations. The surge model is based on predicting damping (logarithmic decrement values) and mode shapes for pressure and flow pulsations of the interactive dynamic system at its various natural acoustic frequencies. The system design is optimized by assuring that all operating points are sufficiently removed from surge, i.e., logarithmic decrements are above certain specified value. The effects of mean flow on acoustic wave propagation, pipe friction, viscothermal dissipation, and pressure losses at various piping locations (junctions, valves, orifices) are accounted for in the model. Results of the computational modeling of a complex centrifugal compressor system is presented. The analytical model is also verified by comparing the analytical results with experimental data.

Effect of Mean Flow on Acoustic Wave Propagation in a Duct with a Periodic Array of Helmholtz Resonators

2020 ◽  
Vol 37 (3) ◽  
pp. 034301
Author(s):  
Jiang-Wei Liu ◽  
Dian-Long Yu ◽  
Hai-Bin Yang ◽  
Hui-Jie Shen ◽  
Ji-Hong Wen
Keyword(s):  
Wave Propagation ◽  
Acoustic Wave ◽  
Periodic Array ◽  
Mean Flow ◽  
Acoustic Wave Propagation ◽  
Helmholtz Resonators
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