A frequency domain analysis method based on the three-dimensional translating-pulsating (3DTP) source Green function is developed to investigate wave loads and free motions of two ships advancing on parallel course ...A frequency domain analysis method based on the three-dimensional translating-pulsating (3DTP) source Green function is developed to investigate wave loads and free motions of two ships advancing on parallel course in waves. Two experiments are carried out respectively to mea- sure the wave loads and the free motions for a pair of side-by- side arranged ship models advancing with an identical speed in head regular waves. For comparison, each model is also tested alone. Predictions obtained by the present solution are found in favorable agreement with the model tests and are more accurate than the traditional method based on the three dimensional pulsating (3DP) source Green function. Numer- ical resonances and peak shift can be found in the 3DP pre- dictions, which result from the wave energy trapped in the gap between two ships and the extremely inhomogeneous wave load distribution on each hull. However, they can be eliminated by 3DTP, in which the speed affects the free sur- face and most of the wave energy can be escaped from the gap. Both the experiment and the present prediction show that hydrodynamic interaction effects on wave loads and free motions are significant. The present solver may serve as a validated tool to predict wave loads and motions of two ves- sels under replenishment at sea, and may help to evaluate the hydrodynamic interaction effects on the ships safety in replenishment operation.展开更多
The self-noise in cavity is tested in the circling tank, prediction method of cavity's self-noise induced by turbulent boundary layer is established. The window's vibration is using the simply supported boundary con...The self-noise in cavity is tested in the circling tank, prediction method of cavity's self-noise induced by turbulent boundary layer is established. The window's vibration is using the simply supported boundary condition, the sound wave in the cavity is expanded using the rigid wall boundary condition, the modal coupling vibration equation between them is established using the radiation boundary condition. The turbulent boundary layer pulsating pressure is random, the self-noise power spectrum in the cavity is solved. Test of self-noise and turbulent pressure is carried out in the circling tank when the flow velocity is 5 m/s and 8 m/s, the result verifies that the theoretical method can predict the real cavity's hydrodynamic noise approximately, the trends are similar, this provides one analytical method for sonar dome's material selection and noise control.展开更多
基金supported by the National Natural Science Foundation of China(50879090)the Key Research Program of Hydrodynamics of China(9140A14030712JB11044)
文摘A frequency domain analysis method based on the three-dimensional translating-pulsating (3DTP) source Green function is developed to investigate wave loads and free motions of two ships advancing on parallel course in waves. Two experiments are carried out respectively to mea- sure the wave loads and the free motions for a pair of side-by- side arranged ship models advancing with an identical speed in head regular waves. For comparison, each model is also tested alone. Predictions obtained by the present solution are found in favorable agreement with the model tests and are more accurate than the traditional method based on the three dimensional pulsating (3DP) source Green function. Numer- ical resonances and peak shift can be found in the 3DP pre- dictions, which result from the wave energy trapped in the gap between two ships and the extremely inhomogeneous wave load distribution on each hull. However, they can be eliminated by 3DTP, in which the speed affects the free sur- face and most of the wave energy can be escaped from the gap. Both the experiment and the present prediction show that hydrodynamic interaction effects on wave loads and free motions are significant. The present solver may serve as a validated tool to predict wave loads and motions of two ves- sels under replenishment at sea, and may help to evaluate the hydrodynamic interaction effects on the ships safety in replenishment operation.
文摘The self-noise in cavity is tested in the circling tank, prediction method of cavity's self-noise induced by turbulent boundary layer is established. The window's vibration is using the simply supported boundary condition, the sound wave in the cavity is expanded using the rigid wall boundary condition, the modal coupling vibration equation between them is established using the radiation boundary condition. The turbulent boundary layer pulsating pressure is random, the self-noise power spectrum in the cavity is solved. Test of self-noise and turbulent pressure is carried out in the circling tank when the flow velocity is 5 m/s and 8 m/s, the result verifies that the theoretical method can predict the real cavity's hydrodynamic noise approximately, the trends are similar, this provides one analytical method for sonar dome's material selection and noise control.