三体船阻力预报与侧体布局的优化

Prediction on Resistance of Trimaran and Side Hull Optimization

三体船具有一系列突出的优点,它优良的快速性、耐波性和稳性等特点为其应用提供了广阔的前景。侧体布局的设计是优化其性能的关键,为了探究其对阻力性能的影响,本文首先在GAMBIT中创建三体船数值模型,再采用FLUENT软件对其进行数值计算。与船模试验相比,数值计算方法的相对误差小于2%,同时能准确高效地捕捉到自由液面波形等流场数据,为三体船阻力预报提供了一种高效可行的方法。在此基础上改变侧体纵横偏距,计算并分析了25种侧体布局方案的兴波干扰情况和阻力性能,得到了侧体布置在主体兴波波峰中时阻力较大,布置在主体兴波波谷中时阻力较小的结论。最后根据阻力最优原则,确定了侧体的最佳布置区域。不仅揭示了侧体布局对三体船阻力的影响规律,还为三体实船的侧体布局设计提供了新的思路。

Trimaran has a series of outstanding merits,its excellent performance of speediness,sea-keeping and stability have made it a wide application.Although the trimaran,a new type of hull form with excellent performance,has received more and more attention,problems still exist in studying its hull form and the arrangement of side hulls is the key factor to optimize its performance.Here,viscous computational fluid dynamics（CFD）technology was applied to research resistance performance of a trimaran.In order to explore the impact on the performance of resistance,the numerical trimaran model was designed first in GAMBIT,then conduct numerical calculation in FLUENT software,while taking free surfaces and flow viscosity into consideration.To validate the simulation results,conduct ship model test to calculate the resistances of the target trimaran with different layouts.And convert the experiment results to the practice ship by the two-dimensional and‘1＋k＇resistance calculation method,then compare the experiment results with the simulation results.Compared with model test results,the relative error of numerical resistance results is less than 2%,at the same time the information of the flow field was accurately captured,such as the waveform of the free surface,proves the reliability of FLUENT in predicting trimaran resistance.Then the wave-making interference and resistance performance for 25 different side hull configurations were computed and analyzed.The results show that the total resistance is higher when the side hulls are arranged in the peak of main hull wave and smaller when arranged in wave trough.In conclusion,the best area for side hull arrangement is signed out based on the principle of total resistance optimization.Not only reveals the influence rules of side hulls arrangement on trimaran resistances,but also offers a new method for the design of trimaran side hulls arrangement.At the same time,an apparent discrepancy in calculated and test results at high Froude numbers shows that the application or the code itself should be improved.