The interaction between wave and horizontal and vertical plates is investigated by the boundary element method, and the relations of wave exciting force with plate thickness, submergence and length are obtained. It is...The interaction between wave and horizontal and vertical plates is investigated by the boundary element method, and the relations of wave exciting force with plate thickness, submergence and length are obtained. It is found that： 1） The efficient wave exciting force exists while plate submergence is less than 0.5 m, and the plate is very thin with order O（0.005 m）. 2） The maximum heave wave exciting force exists, and it is the main factor for surface and submerged horizontal plate while the roll force can be ignored. 3） The maximum sway wave exciting force exists, it is the main factor for surface or submerged vertical plate, and the roll force is about 20 times of horizontal plate.展开更多
The radiation and the diffraction of linear waves by a rectangular structure with an opening at its bottom floating in oblique seas of finite depth are investigated. Analytical expressions for the radiated potentials ...The radiation and the diffraction of linear waves by a rectangular structure with an opening at its bottom floating in oblique seas of finite depth are investigated. Analytical expressions for the radiated potentials and the diffracted potential are obtained by use of the method of separation of variables and the eigenfunction expansion method, with the unknown coefficients being determined by the boundary conditions and the matching requirement on the interface. The hydrodynamic coefficients and the wave excitation forces are verified using the symmetry properties of coupled hydrodynamic coefficients and one specific example investigated previously. By use of the present analytical-numerical solution, the influences of the angle of incidence, the width of the opening on the wave forces and the hydrodynamic coefficients are investigated. It is also found that in the oblique sea the external excitation frequency that can lead to the resonance of a rectangular tank depends on the wave direction and the wave number of the incident wave.展开更多
A 3-D time-domain seakeeping analysis tool has been newly developed by using a higher-order boundary element method with the Rankine source as the kernel function. An iterative time-marching scheme for updating both k...A 3-D time-domain seakeeping analysis tool has been newly developed by using a higher-order boundary element method with the Rankine source as the kernel function. An iterative time-marching scheme for updating both kinematic and dynamic free-surface boundary conditions is adopted for achieving numerical accuracy and stability. A rectangular computational domain moving with the mean speed of ship is introduced. A damping beach at the outer portion of the truncated free surface is installed for satisfying the radiation condition. After numerical convergence checked, the diffraction unsteady problem of a Wigley hull traveling with a constant forward speed in waves is studied. Extensive results including wave exciting forces, wave patterns and pressure distributions on the hull are presented to validate the efficiency and accuracy of the proposed 3-D time-domain iterative Rankine BEM approach. Computed results are compared to be in good agreement with the corresponding experimental data and other published numerical solutions.展开更多
基金supported by Foundation of Science and Technology of Dalian (Grant No. 2008A16GX248)
文摘The interaction between wave and horizontal and vertical plates is investigated by the boundary element method, and the relations of wave exciting force with plate thickness, submergence and length are obtained. It is found that： 1） The efficient wave exciting force exists while plate submergence is less than 0.5 m, and the plate is very thin with order O（0.005 m）. 2） The maximum heave wave exciting force exists, and it is the main factor for surface and submerged horizontal plate while the roll force can be ignored. 3） The maximum sway wave exciting force exists, it is the main factor for surface or submerged vertical plate, and the roll force is about 20 times of horizontal plate.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.51679132,51079082)the Science and Technology Commission of Shanghai Municipality(Grant No.17040501600)
文摘The radiation and the diffraction of linear waves by a rectangular structure with an opening at its bottom floating in oblique seas of finite depth are investigated. Analytical expressions for the radiated potentials and the diffracted potential are obtained by use of the method of separation of variables and the eigenfunction expansion method, with the unknown coefficients being determined by the boundary conditions and the matching requirement on the interface. The hydrodynamic coefficients and the wave excitation forces are verified using the symmetry properties of coupled hydrodynamic coefficients and one specific example investigated previously. By use of the present analytical-numerical solution, the influences of the angle of incidence, the width of the opening on the wave forces and the hydrodynamic coefficients are investigated. It is also found that in the oblique sea the external excitation frequency that can lead to the resonance of a rectangular tank depends on the wave direction and the wave number of the incident wave.
基金supported by the Fundamental Research Developing Association for Shipbuilding and Offshore (REDAS), Japan
文摘A 3-D time-domain seakeeping analysis tool has been newly developed by using a higher-order boundary element method with the Rankine source as the kernel function. An iterative time-marching scheme for updating both kinematic and dynamic free-surface boundary conditions is adopted for achieving numerical accuracy and stability. A rectangular computational domain moving with the mean speed of ship is introduced. A damping beach at the outer portion of the truncated free surface is installed for satisfying the radiation condition. After numerical convergence checked, the diffraction unsteady problem of a Wigley hull traveling with a constant forward speed in waves is studied. Extensive results including wave exciting forces, wave patterns and pressure distributions on the hull are presented to validate the efficiency and accuracy of the proposed 3-D time-domain iterative Rankine BEM approach. Computed results are compared to be in good agreement with the corresponding experimental data and other published numerical solutions.
