Research On The Resistance And Stability Of Trimaran Planing Hull

The paper is originate from item of contrast experiment for resistance of a mono-planinghull, which mainly aims at designing the profile of trimaran planing hull with great resistanceperformance and stability. The resistance performance of trimaran planing hull shouldprecede or be close at least to that of the mono-planing hull. Besides, the trimaran planinghull requires excellent stability, which could sail with safety and stability at high speed orultrahigh speed.In the first stage of this paper three times of resistance tests of trimaran planing hullmodel were carried out. The main principles, scheme states, test phenomenon and resistanceresults of each model were mainly presented. The effect of the changes in certain testparameters such as width of chine and center of gravity in given orders to the resistance oftrimaran planing hull models was analyzed. The phenomenon and results in tests were brieflyanalyzed in mechanism integrated with hull character. Besides, schemes of models withaccessional devices were added in the tests. In contrast to the schemes of models withoutaccessional devices, the effect of installing accessional devices to the resistance of trimaranplaning hull models was ascertained.Based on the three times of model resistance tests, mathematical method and CFDnumerical simulation method were taken to conduct hull form optimization in the secondstage. In mathematical method the formula relation between resistance and each hull formparameter was stepwise regressed by use of model test data. The resistance formula wasrestricted by displacement of model and center of gravity and the minimum was confirmed.The hull form parameters at minimum of formula were selected to draw the profile of model.The three-dimension hull model was compartmentalized with grids in the CFD numericalsimulation method. After setting the solving preferences the CFX solver was applied to putup numerical simulation in order to seek the resistance value at certain speed. Throughvarious schemes due to hull form parameters changes and installation of different steps,comparisons were done. The best scheme in resistance was found and the profile of modelwas drawn. The two profiles obtained by two methods were both made into models and takeninto tests to testify the effect of hull form optimization. It was shown in the test result that the two methods had a distinct effect on optimization and the anticipation goal was gained.In the third stage the stability at high speed was discussed. According to the upper andlower speed limits at which the dolphin motion took place, the limit curve of longitudinalstability of the hull model was obtained by MATLAB linear polynomial fitting. By virtue ofthe scheme with widening the chines, the veracity of limit curve of stability and the feasibilityof this method were proved. In contrast to the limit curve of longitudinal stability of aconventional mono planing hull, the trimaran planing hull had a more excellent longitudinalstability.