A time domain Kelvin source high order panel method based on NURBS is developed and applied to solve the unsteady wave making problems. Numerical results of instant wave resistance and free surface elevation are pr...A time domain Kelvin source high order panel method based on NURBS is developed and applied to solve the unsteady wave making problems. Numerical results of instant wave resistance and free surface elevation are presented and compared with the availaby results by other authors, for submerged spheroid and sphere beneath the free surface and for surface ship of Wigley models moving with unsteady speed. The agreement is satisfying.展开更多
This paper focuses on computations of viscous hydrodynamic forces acting on aship in oblique motion by solving the three-dimensional Reynolds-Averaged Navier-Stokes (RANS)equations. The standard k-ε turbulence model ...This paper focuses on computations of viscous hydrodynamic forces acting on aship in oblique motion by solving the three-dimensional Reynolds-Averaged Navier-Stokes (RANS)equations. The standard k-ε turbulence model with wall function was applied. The conservationequations were discretized by a cell-centered second-order Finite Volume Method (FVM) in ablock-structured body-fitted grid and the coupling of velocity and pressure was resolved with theSIMPLE method. Computations were performed for a Wigley hull model to investigate the viscous flowsaround it. The results show good agreement with experimental data and more reasonable prediction ofhydrodynamic forces and moments than other numerical results available.展开更多
An efficient multi block incompressible viscous flow solver based on solving the Reynolds Averaged Navier Stokes (RANS) equations numerically has been developed that can be applied to simulation of a variety of shi...An efficient multi block incompressible viscous flow solver based on solving the Reynolds Averaged Navier Stokes (RANS) equations numerically has been developed that can be applied to simulation of a variety of ship maneuvering related flows and calculation of hydrodynamic forces. Validation and verification of the solution procedure were carried out on several model problems with good agreement to experimental and numerical results.展开更多
Fuzzy control has shown success in some application areas and emerged as analternative to some conventional control schemes. There are also some drawbacks in this approach,for example it is hard to justify the choice ...Fuzzy control has shown success in some application areas and emerged as analternative to some conventional control schemes. There are also some drawbacks in this approach,for example it is hard to justify the choice of fuzzy controller parameters and control rules, andcontrol precision is low, and so on. Fuzzy control is developing towards self-learning and adaptive.The ship steering motion is a nonlinear, coupling, time-delay complicated system. How to control iteffectively is the problem that many scholars are studying. In this paper, based on the repeatedcontrol of the robot, the self-learning arithmetic was worked out. The arithmetic was realized infuzzy logic way and used in cargo steering. It is the first time for the arithmetic to be used incargo steering. Our simulation results show that the arithmetic is effective and has severalpotential advantages over conventional fuzzy control. This work lays a foundation in modeling andanalyzing the fuzzy learning control system.展开更多
文摘A time domain Kelvin source high order panel method based on NURBS is developed and applied to solve the unsteady wave making problems. Numerical results of instant wave resistance and free surface elevation are presented and compared with the availaby results by other authors, for submerged spheroid and sphere beneath the free surface and for surface ship of Wigley models moving with unsteady speed. The agreement is satisfying.
文摘This paper focuses on computations of viscous hydrodynamic forces acting on aship in oblique motion by solving the three-dimensional Reynolds-Averaged Navier-Stokes (RANS)equations. The standard k-ε turbulence model with wall function was applied. The conservationequations were discretized by a cell-centered second-order Finite Volume Method (FVM) in ablock-structured body-fitted grid and the coupling of velocity and pressure was resolved with theSIMPLE method. Computations were performed for a Wigley hull model to investigate the viscous flowsaround it. The results show good agreement with experimental data and more reasonable prediction ofhydrodynamic forces and moments than other numerical results available.
文摘An efficient multi block incompressible viscous flow solver based on solving the Reynolds Averaged Navier Stokes (RANS) equations numerically has been developed that can be applied to simulation of a variety of ship maneuvering related flows and calculation of hydrodynamic forces. Validation and verification of the solution procedure were carried out on several model problems with good agreement to experimental and numerical results.
文摘Fuzzy control has shown success in some application areas and emerged as analternative to some conventional control schemes. There are also some drawbacks in this approach,for example it is hard to justify the choice of fuzzy controller parameters and control rules, andcontrol precision is low, and so on. Fuzzy control is developing towards self-learning and adaptive.The ship steering motion is a nonlinear, coupling, time-delay complicated system. How to control iteffectively is the problem that many scholars are studying. In this paper, based on the repeatedcontrol of the robot, the self-learning arithmetic was worked out. The arithmetic was realized infuzzy logic way and used in cargo steering. It is the first time for the arithmetic to be used incargo steering. Our simulation results show that the arithmetic is effective and has severalpotential advantages over conventional fuzzy control. This work lays a foundation in modeling andanalyzing the fuzzy learning control system.
