Acoustic scattering from an infinitely long cylindrical shell with periodic internal lengthwise ribs

2020 ◽  
Vol 148 (2) ◽  
pp. 984-997
Author(s):  
Yunzhe Tong ◽  
Bin Wang ◽  
Jun Fan ◽  
Benqi Liu ◽  
Xiefan Pan
Keyword(s):  
Cylindrical Shell ◽  
Acoustic Scattering ◽  
Long Cylindrical Shell

scholarly journals Simulation and analysis on low-frequency scattering characteristics of the finite cylindrical shell in shallow water

2019 ◽  
Vol 283 ◽  
pp. 03007
Author(s):  
Jinyu Li ◽  
Dejiang Shang ◽  
Yan Xiao
Keyword(s):  
Cylindrical Shell ◽  
Free Space ◽  
Acoustic Scattering ◽  
Low Frequency ◽  
Target Strength ◽  
Wave Direction ◽  
Scattering Field ◽  
Simulation Results ◽  
Finite Cylindrical Shell ◽  
Target Locations

Low-frequency acoustic scatterings from a finite cylindrical shell are numerically analyzed by FEM. The simulation results show that the acoustic-scattering field in waveguide has lots of frequency-related sidelobes, while no sidelobes exist in free space at low frequencies. The simulation also indicates that the module value in waveguide can be almost 20 dB larger than that in free space at low frequency, which is caused by the ocean boundaries. We also demonstrate that when the incident wave direction is normal to the target at low frequency, the target strength will be maximum and the distribution of the acoustic-scattering field is axisymmetric about the incident waving direction. Meanwhile, the acoustic-scattering field is also related to the impedance of the seabed, and the change of the impedance makes just a little contribution to the scattering field. Finally, the influence of different target locations is analyzed, including the targets near the sea surface, seabed and the middle region of the ocean waveguide, respectively. From simulation results, it is evident that the distribution of the acoustic-scattering field at low frequency has a little difference, which is smaller than 0.5 dB with various target locations, and the change is frequency and boundary-related.

scholarly journals A NOTE ON THE CYLINDRICAL COLLAPSE OF COUNTER-ROTATING DUST

2002 ◽  
Vol 11 (09) ◽  
pp. 1469-1477 ◽  
Author(s):  
SÉRGIO M. C. V. GONÇALVES ◽  
SANJAY JHINGAN
Keyword(s):  
Cylindrical Shell ◽  
Initial Data ◽  
Analytical Solutions ◽  
Curvature Singularity ◽  
Apparent Horizons ◽  
Long Cylindrical Shell ◽  
Hoop Conjecture ◽  
Cylindrical Collapse

We find analytical solutions describing the collapse of an infinitely long cylindrical shell of counter-rotating dust. We show that — for the classes of solutions discussed herein — from regular initial data a curvature singularity inevitably develops, and no apparent horizons form, thus in accord with the spirit of the hoop conjecture.

Analysis of the acoustic scattering at variable incidences from an extra thin cylindrical shell bounded by hemispherical endcaps

2000 ◽  
Vol 108 (5) ◽  
pp. 2187-2196 ◽  
Author(s):  
N. Touraine ◽  
L. Haumesser ◽  
D. Décultot ◽  
G. Maze ◽  
A. Klauson ◽  
...  
Keyword(s):  
Cylindrical Shell ◽  
Acoustic Scattering ◽  
Thin Cylindrical Shell
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