When is a flow compressible? compressible flow differs from an incompressible one in that significant change happens in the density

量纲齐次性原理 同一方程中各项的量纲必须相同。用基本量纲的幂次式表示时, 每个基本量纲的幂次应相等,称为量纲齐次性

一、湍流流动的主要特点 （1)湍流流场具有完全不规则的瞬息变化的运动特征。 （2)湍流流场中,各种物理量都是随时间和空间变化的随机量。 （3)湍流流场中,流体微团的随机运动在足够长的时间内服从某种数学统计规律。空间点上任一瞬时物理量均可用平均值与脉动值之和来表示,即

1分类 2比较

Chapter 4 Differential Relations For Viscous Flow 4.1 Preliminary Remarks Two ways in analyzing fluid motion (1)Seeking an estimate of gross effects over a finite region or control volume. Integral ()Seeking the point-by-point details of a flow pattern by analyzing an infinitesimal region of the flow

Boundary layer(边界层) Although frictional effects in slightly viscous fluid are indeed present, they are confined to a thin layer near the surface of the body, and the rest of the flow can be considered inviscid. (1904, Prandt/)

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

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)

第一章实验基础知 第二章实验内容 实验一、流体流动阻力测定 实验二、离心泵特性曲线测 实验三、恒压过滤常数测定实验 实验四对流给热系数测 实验七干燥速率曲线的测

第一节变质作用的因素 变质作用一一地壳中已经形成的岩石在基本上处于固体状态下,受到温度、压力及化学活动行流体的作用,发生矿物成分,化学成分,岩石结构和构造变化的地质作用