轴对称体大角度斜出水的非线性摄动解

本文处理的是轴对称体大角度斜出水三元非线性问题,以出水角的余角α为小参数进行摄动展开,化为二维非线性问题求解.给出了零阶、一阶和二阶解的积分形式.其中零阶解对应于轴对称体垂直出水的情况,仍是非线性的.数值结果给出了不同Froude数、物体不同长细比情况下各阶自由面形状及各阶力的变化过程.     

用E-L方法计算圆平头物体垂直入水空泡的面闭合和深闭合

本文根据非线性自由面理论,用E-L方法计算了圆平头物体垂直入水空泡发生、发展、面闭合、拉离和深闭合等一系列连续变化过程。空泡中气体流动分为三个阶段加以处理。采用Riabouchinsky映象板模型,初步解决了高F_r数下数值模拟空泡深闭合的困难。计算结果表明,对于给定的物体头型,F_r数、空气出度数、物体质量数是影响入水空泡发展过程的主要因素。     

导弹水下发射燃气泡计算

采用一维非定常气流场模型和轴对称理想水流场模型，对水下发射导弹的尾部非定常燃气泡内外流场进行了耦合数值求解。考虑了高温燃气与水介质之间的传热、汽化等对泡内气体流动的影响，数值模拟了燃气泡的生长和脱落过程，揭示了燃气泡中气体流动的基本规律，计算了燃气泡发展对导弹所受水动力的影响。     

轴对称体垂直出水的非线性数值解

根据格林定理,本文采用严格的非线性边界条件,对任意形状的轴对称体的垂直出水,包括水下运动、接近液面、穿出液面的全过程进行了数值计算。计算结果与实验结果比较表明,非线性计算结果是可信的。     

Perturbation solution to the nonlinear problem of oblique water exit of an axisymmetric body with a large exit-angle

In this paper,a nonlinear,unsteady3-D free surface problem of the oblique water exitof an axisymmetric body with a large water exit-angle was investigated by means of theperturbation method in which the complementary angle a of the water exit angle waschosen as a small parameter.The original3-D problem was solved by expanding it into apower series of a and reduced to a number of2-D problems.The integral expressions forthe first three order solutions were given in terms of the complete elliptic functions of thefirst and second kinds.The zeroth-order solution didn‘t turn out to be a linear problem asusual but a nonlinear one corresponding to the vertical water exit for the same body.Computational results were presented for the free surface shapes and the forces exerted upto the second order during the oblique water exit of a series of ellipsoids with various ratiosof length to diameter at different Froude numbers.