Two different points of view in analyzing problems in mechanics The Eulerian view(欧拉观点) and the Lagrangian view(拉格朗日观点) Flow classification Streamline(流线)Pathline(迹线)& Flowfield (流场)流线方程计算流谱 Surface force(表面力) and body force(质量力,体积力)
Chapter3 Integral Relations(积分关系式) for a Control Volume in One-dimensional Steady Flows 3.1 Systems(体系) versus Control Volumes(控制体) System: an arbitrary quantity of mass of fixed identity. Everything external to this system is denoted by the term surroundings, and the system is separated from its surroundings by it's boundaries through which no mass