scholarly journals Acoustic scattering from an infinitely long cylindrical shell with an internal mass attached by multiple axisymmetrically distributed stiffeners

2015 ◽  
Vol 338 ◽  
pp. 134-153 ◽  
Author(s):  
Alexey S. Titovich ◽  
Andrew N. Norris
2020 ◽  
Vol 148 (2) ◽  
pp. 984-997
Author(s):  
Yunzhe Tong ◽  
Bin Wang ◽  
Jun Fan ◽  
Benqi Liu ◽  
Xiefan Pan

2019 ◽  
Vol 283 ◽  
pp. 03007
Author(s):  
Jinyu Li ◽  
Dejiang Shang ◽  
Yan Xiao

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.


2002 ◽  
Vol 11 (09) ◽  
pp. 1469-1477 ◽  
Author(s):  
SÉRGIO M. C. V. GONÇALVES ◽  
SANJAY JHINGAN

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.


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

Sign in / Sign up

Export Citation Format

Share Document