Research On The Dynamic Characteristic Of High Speed Trimaran

As a new ship type of good capability, the high-speed trimaran has recently been attracting the world's attention. Because of its particular type, good capability and technical and tactical performance, the high-speed trimaran will have wide application future in the fields of warship and civil ship, and is even thought to be aircraft carrier. Like ordinary ships, when it sails in the water, harmful vibration may also occur due to all kinds of drive, which leads to contradiction with more and more requirement in the ship quality, usage performance and shipman's habitation. Thus, the overall vibration performance of high-speed trimaran must be calculated in the course of ship design, so that reasonable scheme and necessary measures can be taken to prevent the harmful vibration.For the preliminary designed high-speed trimaran, the added water mass and modality of trimaran overall vibration have been analyzed by means of the hydrodynamic software FLUENT and the finite element software ANSYS in this paper. The main work is as follows:The theory of single cylinder added water mass and the experiment research on twin cylinders added water mass referred to, the added water mass of ternate cylinders has been calculated in this paper. From the calculation, it can be included that when S/D₁ is more than one but less than six,φ₁₂ andφ₃ both gradually decrease with S/D₁ increasing, but both are more than one, that is to say, the added water mass of ternate cylinders is more than the sum of that of three single cylinders of the same dimension, which means that the space S has influence on the added water mass. It's deduced that the side hulls will make the added water mass of trimaran increase, and the equation of the added water mass of unit length of the trimaran vertical vibration is obtained from the preliminary fitting of the calculation results.For the preliminary designed high-speed trimaran, dry and wet modalities have been calculated in the paper. Because the added water mass only influence the frequency, but not the free vibration shape, the first four overall vibration shapes have been obtained by dry modality calculation.