【作者】 王新宇；

【导师】 朱仁传；

【作者基本信息】 上海交通大学 ， 船舶与海洋工程， 2017， 硕士

【摘要】 船舶在实际航行过程中,往往会遇到浅海、湖泊、内河等水域,其特点是水深是有限的。对于上述水域中行驶的船舶,受船体周围流场变化的影响,其兴波阻力与船舶在无限水深水域中航行时的兴波阻力相比有明显的差别。船舶在静水中行驶时,所受的流体动压力沿船体表面分布不均衡,从而导致其航行姿态发生改变,特别是在水深有限的水域中行驶时,船舶会有伴有明显的纵倾和下沉现象。船舶航行姿态变化会影响其操纵性,当水深较浅时,较大的纵倾和下沉会导致船舶发生触底现象,将严重威胁船员的生命财产安全。我国海域辽阔,有漫长的海岸线,内河湖泊众多且分布范围十分广泛,存在大量浅水水域,因此能够准确地预报兴波阻力及航行姿态对船舶在浅水中的性能和安全的研究有重要意义。论文在三维势流理论基础上,采用高阶面元法数值求解浅水中的非线性船行波问题,其中自由面处理采用了不显含波高的联合非线性条件,保留全部的非线性项,通过定常迭代不断调整波高,使自由面条件在真实波面上满足,同时物面条件也在船舶实际湿表面满足,将船舶关于水底镜像来满足底部边界条件,通过配置点前移的数值手段满足辐射条件。迭代过程中船舶湿表面网格通过对基础型值数据进行三次B样条插值自动划分。为提高求解效率,采用单机并行计算的方法组装系数矩阵,采用不完全LU分解的预处理GMRES迭代法求解离散的边界积分方程组。采用上述方法,编写兴波阻力数值预报程序,分别就无限水深和有限水深的非线性船行波问题进行计算。水深无限时,线性和非线性计算Wigley、S60和KCS三种船型的兴波阻力、姿态、自由面波形等与他人发表的实验数据和计算结果对比,结果吻合良好,验证计算方法的可靠性,有限水深域中线性和非线性计算了不同水深不同航速的Wigley和S60船行波波形及船体阻力,通过并对比分析了水深航速等因素对自由面波形和船舶兴波阻力的影响。更多还原

【Abstract】 Modern ship is always sailing in the neritic sea,lakes and rivers where there are boundaries on the bottom or beside the ship,which called restricted water.Because of the flow around ship changed,the wave-making resistance in the above-mentioned water area will be different compared with it in deep water.When ship moves in static water,the ship attitude will change due to the unbalanced distribution of hydrodynamic pressure along the hull surface.Especially in restricted water,the trim and heave will be obviously.In the shallow water,the ship will touch the bottom with large sinkage and trim,which threating people’s life and property security.There are vast sea areas,extended coastline,rivers and lakes in our country,so it has very important practical significance to accurately forecasting the wave-making resistance and ship attitude.The nonlinear method for ship waves based on the high order panel method is shown in the present paper.The combined free surface condition is adopted with all nonlinear terms remained.At each iteration,nonlinear free surface condition and hull surface condition are satisfied on real surface.The bottom boundary is satisfied by the method of images and the radiation condition is satisfied by shift the collocation pionts forward.Bspline surface interpolation is applied to original offsets data to automatically generate hull mesh during iterations.A preconditioned Generalized Minimal Residual method(GMRES)is employed to solve the resulting boundary integral equation in order to improve efficiency.Adoped the method mentioned above,the Fortran code is developed.The present method has been applied to both infinite and finite water depth ship wave problems.In the infinite water depth,the wave drag,sinkage,trim and wave profile of Wigley and S60 hull have been calculated and the numerical results are in good agreement with experimental data.In the finite water depth,the method has been applied for wigley hull wave drag and wave profile for varying water depth and speed and the effects of water depth to wave resistance and wave profile have been discussed.更多还原