<div style="text-align:justify;"> Titanium alloy materials are widely used in the marine and aviation fields due to their excellent properties. The submersible sailing on the water surface is faster th...<div style="text-align:justify;"> Titanium alloy materials are widely used in the marine and aviation fields due to their excellent properties. The submersible sailing on the water surface is faster than underwater diving, so once an accident occurs, the consequences are unimaginable. Based on the failure criterion of the J-K model, this paper uses finite element simulation software to study the impact of impact velocity and impact angle on the collision response of a titanium alloy cylindrical pressure shell, providing a reference for the deep sea titanium alloy pressure shell. </div>展开更多
In this paper, analytical formularions of radiated sound pressure of ring-stiffenedcylindrical shells in fluid medium are derived by means of Hamilton's principleHuygens principle and Green function . These formul...In this paper, analytical formularions of radiated sound pressure of ring-stiffenedcylindrical shells in fluid medium are derived by means of Hamilton's principleHuygens principle and Green function . These formulations Can be used to compute the sound pressure of the shell's surface nearfield and farfield.展开更多
Applying the wavenumber frequency transfer function to describe the whole system including tht elastic cylindrical shell and the fluid loading, a general expression of the cross spectrum of the interior noise induced ...Applying the wavenumber frequency transfer function to describe the whole system including tht elastic cylindrical shell and the fluid loading, a general expression of the cross spectrum of the interior noise induced by the TBL (turbulent boundary layer) pressure fiuctuations is derived. There are two production mechanisms of the noise: one is direct transfer of the convective ridge of the pressure fluctuations through the shell, the other is the reradiation of resonance modes excited by the pressure fluctuations. At low frequencies the noise produced by the latter mechanism is dominant. Solving the frequency equation of the cylindrical shell with liquid loading, the two Stoneley-type poles in the complex K plane are presented. They are the major sources of the reradiation of shell at low frequencies. Finally, effects of the shell radius, shell thickness, absorption of material and the flow speeds on the noise reduction are computed by numerical iniegration.展开更多
Finite hydrophone and hydrophone array are the wave vector filter and can re-duce the flow noise. In this paper the responses of the cylindrical area hydrophone and two-circular area hydrophone within viscoelastic cyl...Finite hydrophone and hydrophone array are the wave vector filter and can re-duce the flow noise. In this paper the responses of the cylindrical area hydrophone and two-circular area hydrophone within viscoelastic cylindrical shell to the TBL (turbulent boundary layer) pressure fluctuations are investigated. Applying the method based on the wavenumber frequency spectrum analysis, the expressions of 1) the noise power spectrum of a single hy-drophone; 2) the space correlation of two hydrophones; 3) the noise power spectrum of array are derived. The dependencies of the noise reduction on hydrophone shape, dimension, element amount and separation of hydrophones of array are calculated by numerical integration. The wide-band and narrow-band correlation for two hydrophones is also calculated. The numerical results show that hydrophone array can effectively reduce the interior noise.展开更多
文摘<div style="text-align:justify;"> Titanium alloy materials are widely used in the marine and aviation fields due to their excellent properties. The submersible sailing on the water surface is faster than underwater diving, so once an accident occurs, the consequences are unimaginable. Based on the failure criterion of the J-K model, this paper uses finite element simulation software to study the impact of impact velocity and impact angle on the collision response of a titanium alloy cylindrical pressure shell, providing a reference for the deep sea titanium alloy pressure shell. </div>
文摘In this paper, analytical formularions of radiated sound pressure of ring-stiffenedcylindrical shells in fluid medium are derived by means of Hamilton's principleHuygens principle and Green function . These formulations Can be used to compute the sound pressure of the shell's surface nearfield and farfield.
文摘Applying the wavenumber frequency transfer function to describe the whole system including tht elastic cylindrical shell and the fluid loading, a general expression of the cross spectrum of the interior noise induced by the TBL (turbulent boundary layer) pressure fiuctuations is derived. There are two production mechanisms of the noise: one is direct transfer of the convective ridge of the pressure fluctuations through the shell, the other is the reradiation of resonance modes excited by the pressure fluctuations. At low frequencies the noise produced by the latter mechanism is dominant. Solving the frequency equation of the cylindrical shell with liquid loading, the two Stoneley-type poles in the complex K plane are presented. They are the major sources of the reradiation of shell at low frequencies. Finally, effects of the shell radius, shell thickness, absorption of material and the flow speeds on the noise reduction are computed by numerical iniegration.
文摘Finite hydrophone and hydrophone array are the wave vector filter and can re-duce the flow noise. In this paper the responses of the cylindrical area hydrophone and two-circular area hydrophone within viscoelastic cylindrical shell to the TBL (turbulent boundary layer) pressure fluctuations are investigated. Applying the method based on the wavenumber frequency spectrum analysis, the expressions of 1) the noise power spectrum of a single hy-drophone; 2) the space correlation of two hydrophones; 3) the noise power spectrum of array are derived. The dependencies of the noise reduction on hydrophone shape, dimension, element amount and separation of hydrophones of array are calculated by numerical integration. The wide-band and narrow-band correlation for two hydrophones is also calculated. The numerical results show that hydrophone array can effectively reduce the interior noise.
