The problem of shore wash in environmental engineering is connected in particular with the effect of waves generated by the ships and fast speed boats. Another problem is protection of ＂Marines＂ with anchored boat a...The problem of shore wash in environmental engineering is connected in particular with the effect of waves generated by the ships and fast speed boats. Another problem is protection of ＂Marines＂ with anchored boat against waves. Sloping banks provoke unfavorable transformation of waves. Simultaneously sloping bank is the factor which significantly complicates prediction of wave pattern in numerical analysis. The purpose of present paper is to demonstrate the results of numerical investigation of ship waves pattern in constrain water area with slope banks by panel method for non-linear ship waves calculation usually applied for ship hull perfection as routine instrument of towing tanks technology. The method initially developed for calculation of ship hull waves in inviscid infinite fluid was adapted to meet boundary conditions on slope banks. Verification of the method was done for 60-series ship in rectangular channel. Development of wave pattern generated by two ship of different types--monohull ferries and river catamaran was investigated. It was found that ship waves height significantly increased due to slopping banks comparing with case of deep water and shallow water rectangular channel.展开更多
The wash-out filter （WF） technique is used to control the flutter of a two dimensional airfoil with cubic non-linearity in incompressible flow. Firstly, Hopf bifurcation theory is used to determine the point at whic...The wash-out filter （WF） technique is used to control the flutter of a two dimensional airfoil with cubic non-linearity in incompressible flow. Firstly, Hopf bifurcation theory is used to determine the point at which the nonlinear controller is introduced. The system is then transformed into Jordan canonical form, based on analysis of linearized eigenvalues of the system. Secondly, for the introduced WF controller, the linear control gain is determined according to Hopf bifurcation condition. The sym- bolic computing program of normal form direct method （NFDM） is also used to obtain the normal form of the controlled system. The non-linear control gain can be determined based on the relation of the type of bifurcation and the parameters of the normal form, to transform sub-critical Hopf bifurcation to be su- per-critical one. Lastly, numerical simulations are used to certify the validity of theoretical analysis, in which the amplitude of flutter or limit cycle of the controlled system is reduced greatly, comparing to the original system.展开更多
文摘The problem of shore wash in environmental engineering is connected in particular with the effect of waves generated by the ships and fast speed boats. Another problem is protection of ＂Marines＂ with anchored boat against waves. Sloping banks provoke unfavorable transformation of waves. Simultaneously sloping bank is the factor which significantly complicates prediction of wave pattern in numerical analysis. The purpose of present paper is to demonstrate the results of numerical investigation of ship waves pattern in constrain water area with slope banks by panel method for non-linear ship waves calculation usually applied for ship hull perfection as routine instrument of towing tanks technology. The method initially developed for calculation of ship hull waves in inviscid infinite fluid was adapted to meet boundary conditions on slope banks. Verification of the method was done for 60-series ship in rectangular channel. Development of wave pattern generated by two ship of different types--monohull ferries and river catamaran was investigated. It was found that ship waves height significantly increased due to slopping banks comparing with case of deep water and shallow water rectangular channel.
文摘The wash-out filter （WF） technique is used to control the flutter of a two dimensional airfoil with cubic non-linearity in incompressible flow. Firstly, Hopf bifurcation theory is used to determine the point at which the nonlinear controller is introduced. The system is then transformed into Jordan canonical form, based on analysis of linearized eigenvalues of the system. Secondly, for the introduced WF controller, the linear control gain is determined according to Hopf bifurcation condition. The sym- bolic computing program of normal form direct method （NFDM） is also used to obtain the normal form of the controlled system. The non-linear control gain can be determined based on the relation of the type of bifurcation and the parameters of the normal form, to transform sub-critical Hopf bifurcation to be su- per-critical one. Lastly, numerical simulations are used to certify the validity of theoretical analysis, in which the amplitude of flutter or limit cycle of the controlled system is reduced greatly, comparing to the original system.
