A brief history of the expanded application of multi-hull ships and boats is shown. The possibilities of catamaran development are proposed. The first line of multi-hull development is the wider use of various types of multi-hulls. The second line of development is a special method of designing, including complex comparison of seaworthiness. The proposed method ensures the elimination of the disadvantages of multi-hulls, and the fullest realization of their advantages. Practical examples of the developments are shown.
This research is targeted to improve the semi-submersible heave response prediction by using diffraction potential theory by involving drag effect in the calculation. The comparison to the experimental result was observed that heave motion tendency predicted by the diffraction potential theory is no agreed with motion experimental result when the heave motion is dominated by damping. In this research, the viscous damping and drag force for heave motion is calculated from the drag term of Morison equation. The nonlinear drag term in Morison equation is linearized by Fourier series linearization method and then inserted into the motion equation to correct the inadequate of diffraction potential theory. The proposed numerical method is also applied to simulate the semi-submersible motion response to obtain the heave motion tendency predicted by this numerical method. In comparison to the experimental result which tested at the same wave condition obtained that the diffraction potential theory with the Morison drag term correcting is able to provide satisfying heave response result especially in damping dominated region.
Department of Aeronautics, Automotive and Ocean Engineering, Faculty of Mechanical Engineering, Universiti Teknologi Malaysia, Malaysia
Ocean and Aerospace Engineering Research Institute, Indonesia
Historically speaking, all high frequency earth-quakes do not produce tsunami which is evident from several earthquakes that took place in Indian Ocean between 2004 and 2006. The works of Geist et.al [’06] and Ammon et.al [’05] are good examples of such study through which they have also pointed out the miserable failures of the existing warning system. The reasons of no-generation of tsunami due to large quakes may be several but in this article we have tried to throw some light on this puzzle and tried to analyze energy transmission to a tsunami motion at steady state and have shown that no energy transmits for certain frequencies of the forcing parameter. We discuss here tsunami waves which are generated instantaneous bottom dislocation where the ocean floor is taken to be of variable slope and analytical solutions are provided correct to all time t.
Department of Mathematics, Khalisani College, Chandannagar, Hooghly, India – 712 138
Baidyapur Ramkrishna Vidyapith , Baidyapur, Burdwan, India – 713 122
This paper studied on Wave Buoy Legged Spider power device, a floating wave energy system based on linear generator. The device contains horizontal cylinders arranged such that it looks like the legs of a spider. Inside cylinders will be equipped with a linear generator. During wave motions, some rotors of the linear generators slide forward and backward, thus generating electricity. As a case, a conceptual design of the Wave Buoy Legged Spider device using floating balls of Malaysian wave buoy for an ocean site in Terengganu, West Malaysia is presented. The wave energy was approximately assessed based on observed wave data. Furthermore a method to determine the directional wave spectra by using nonlinear programming has been proposed with introducing a correction factor in order to avoid the concentration of power spectral density. The capability of this method has been verified by the analysis with the data of the experiments of the floating ball response.
Department of Aeronautics, Automotive and Ocean Engineering, Faculty of Mechanical Engineering, Universiti Teknologi Malaysia, Malaysia
Marine Technology Center, Universiti Teknologi Malaysia, Malaysia
Ocean and Aerospace Engineering Research Institute, Indonesia
