In this paper the basic principle of the method of characteristics is described , and is constructed an explicit scheme for dam break simulation of one - dimensional dam instant all break waves flow of a low dam with rectangle section and a huge dam with trapezia section , and of two - dimensional dam instant part break waves flow with simplest space operator splitting 本文模拟了一维矩形断面低坝和梯形断面巨型坝瞬间全溃的洪水波演进过程，给出了与分析解的比较，并结合算子分裂的特征线法对二维瞬间部分溃坝时洪水波的演进过程进行了数值模拟。
( 3 ) in terms of flowing characteristic of drilling fluids on the roller screen , the flowing equations at the axis direction and the tangent direction and the flowing through the screen , and the continuously flowing equation of drilling fluids are built . the characteristic - difference equations of flowing model for drilling fluids are given and the theoretical analysis is made ( 3 )根据钻井液在筒式筛网上的流动特点，建立了筒式筛网上钻井液沿轴线方向流动、周向流动和透筛流动的流动方程，以及钻井液的连续流动方程，利用特征线法写出了筒式网上钻井液流动模型的特征差分方程，并作了理论分析。
On account that models of conduit system and hydro turbine are oversimplified , first of all the detail models of complex conduit system and hydro turbine are summed up , and then the detail models of hydraulic system and power system which are fit for the large disturbance transient calculation are established , including auto modeling models of complex conduit system based on the characteristic equations , linear and nonlinear models of francies " hydro turbine , surge tank ' s current model and generator ' s model , governor ' s model , excitation system ' s model and grids " model in the thesis 鉴于电力系统研究中输水系统和水轮机模型过于简单的情况，本文首先归纳引入了复杂输水系统和水轮机的详细模型，建立了适合大扰动动态过程计算的水电系统详细数学模型，包括基于特征线法的复杂输水系统自动建模模型、混流式水轮机的线性模型和非线性模型、调压井通用模型、同步发电机模型、调速器模型、励磁系统模型和电网模型等。
Corresponding to the correct water hammer mathematic model ( 3 ) , the character difference equation is by comparing the new mathematic model with the old mathematic model , the last calculative part of paper argues the falseness of the current water hammer mathematic model , makes use of the improved character line method to analyze the correct mathematic model ( 3 ) , studies all kinds of facts " impact on water hammer pressure value and water hammer phenomenon attenuation , points out that , in the long pipeline system , the subarea calculation of head loss along with flow rather influences the calculative results of water hammer pressure , advices to take the subarea calculation of head loss along with flow into account in the water hammer calculation of the long pipeline system 对应于正确的水击数学模型( 3 )的特征差分方程形式如下c ，弓+吼川一c ，唱一几弓扮几rv另卜川= o几代+吼川一几唱一吼嵘{一c :脚丸}唱} ? “本论文在最后的计算部分，通过对新老数学模型的数值计算比较，进一步论证了当前水击数学模型的不正确性。并且应用改善了的特征线法对正确的数学模型( 3 )进行了计算分析，研究了各种因素对水击压强值和水击现象衰减的影响，指出在长管道系统中，沿程水头损失的分区计算对水击压强的计算结果影响较大，建议在长管道系统的水击计算中应按分区进行沿程水头损失的计算。
Comparing its results with those by ls - d yna , the accuracy of this algorithm was presented . moreover the failure process in concrete due to impact loading and the failure process of a steel bullet penetrating a concrete circular plane was demonstrated , which presented the dynamic transitional process from continuum to non - continuum . several different fundamental damage forms simulated by using this algorithm were discussed , comparing with the results from experiments 应用该模型对正交各向异性平板内的应力波传播、冲击载荷下混凝土平板的破坏以及钢弹侵彻混凝土圆板的破坏问题进行了研究，通过将计算结果与ls - dyna 、特征线法以及实验结果进行对比，证明了该模型的精确性和可靠性。
Furthermore using the variation principle in the elasticity , the wave - motion equation is derived in the finite deformation elastic thin rod with viscous and transverse inertia effects , and the characteristic curves and their characteristic relations are obtained by characteristic line method , and the influence of viscous and geometrical - dispersive effects on the propagation of wave is analyzed 再利用弹性力学中的变分原理，导出了同时计及粘性和横向惯性效应时的弹性细杆的几何非线性波的波动方程，用特征线法得到它的特征线和特征线上的相容关系，分析了粘性耗散和几何弥散效应对波的传播速度的影响。
The article elaborates the operation principle and application of the resonant intake manifold , and summarizes development on its pressure wave action simulation . its mathematical model is set up as well . in order to calculate unsteady flow in it for multi - cylinder engine , the method of characteristics and the two step lax - wendroff method are integrated to program in visual basic 本文阐述了谐振进气系统的工作原理及应用，综述了谐振进气系统压力波模拟计算方法的发展，建立了谐振进气系统的数学模型，并结合特征线法和lw2差分法，编制了计算多缸机非等熵不定常进气流动的visuaibasic程序，得出的计算结果0与实测0误差小于2 。
