《流体力学 Fluid Mechanics》课程PPT教学课件（双语版）第一章 流体及其主要物理性质

Fluid Mechanics Chapterl A Fluid and Its Mainly Physical Properties

1 Fluid Mechanics

体力学 第一章流体及其主要 物理性质

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Chapter 1 Fluid Particle and Its Mainly physical properties §1-1 Introduction 81-2 Fluid Particle and Continuous Medium Hypothesis 81-3 Density, Specific Volume and Relative density of a Fluid 81-4 Compressibility and Expansion of a Fluid §1-5 FluidⅤ / iscosity 81-6 Forces acting on a Fluid Exercises of Chapter 1

3 Chapter 1 Fluid Particle and Its Mainly Physical Properties §1–1 Introduction §1–2 Fluid Particle and Continuous Medium Hypothesis §1–3 Density , Specific Volume and Relative Density of a Fluid §1–4 Compressibility and Expansion of a Fluid §1–5 Fluid Viscosity §1–6 Forces acting on a Fluid Exercises of Chapter 1

第一章流体质点及其主要物理性质 §1-1引 §1-2流体质点与连续介质假设 §1-3流体的密度、比体积和相对密度 §1-4流体的压缩性和膨胀性 §1-5流体的粘性 §1-6作用在流体上的力 第一章习题

4 第一章 流体质点及其主要物理性质 §1–1 引言 §1–2 流体质点与连续介质假设 §1–3 流体的密度、比体积和相对密度 §1–4 流体的压缩性和膨胀性 §1–5 流体的粘性 §1–6 作用在流体上的力 第一章 习 题

Fluid Partideandlts Mainly Pnysical characters. Chapter 1 Fluid Particle and Its Mainly physical Properties 81-1 Introduction The physical properties of a fluid are determined by the internal reasons of fluid equilibrium and motion regulations, so we should first know the concepts and the mainly physical properties of a fluid before discussing the regulations of fluid mechanics

5 The physical properties of a fluid are determined by the internal reasons of fluid equilibrium and motion regulations, so we should first know the concepts and the mainly physical properties of a fluid before discussing the regulations of fluid mechanics. Chapter 1 Fluid Particle and Its Mainly Physical Properties §1-1 Introduction

流体及其要物性质 第一章流体质点及其主要物理性质 §1-1引言 流体的物理性质决定于流体平衡和运动规律的内部原因, 因此在没有讨论流体力学规律之前,应首先了解流体的概念和 流体的主要物理性质

6 流体的物理性质决定于流体平衡和运动规律的内部原因， 因此在没有讨论流体力学规律之前，应首先了解流体的概念和 流体的主要物理性质。 第一章 流体质点及其主要物理性质 §1-1 引言

Fluid PartideandIts Mainly Physical Charadters 81-2 Fluid Particle and Continuous Medium Hypothesis 1. The physical properties of fluid liquid fluid g ras Fluid and solid are different forms of material. They all have the following basic attributes of material 1. Composed of a great deal of molecules 2. Molecules do random movements continuously 3. The molecule force exists between molecules 7

7 Fluid and solid are different forms of material. They all have the following basic attributes of material : §1-2 Fluid Particle and Continuous Medium Hypothesis 1. The physical properties of fluid 1.Composed of a great deal of molecules. 2.Molecules do random movements continuously . 3.The molecule force exists between molecules. fluid liquid gas   

流你点物性质 §1-2流体质点与连续介质假设 流体的物理属性 液体 流体 气体 流体与固体是物质的不同表现形式,它们都有下列物质基 本属性 1由大量分子组成; 2分子不断作随机热运动; 3分子与分子之间存在着分子力的作用

8 流体与固体是物质的不同表现形式，它们都有下列物质基 本属性： §1-2 流体质点与连续介质假设 一、流体的物理属性 1.由大量分子组成； 2.分子不断作随机热运动； 3.分子与分子之间存在着分子力的作用。 流体    气体 液体

But these three basic properties of materials expressing in gas liquid and solid have difference in quantity and quality In the same volume the number of gas molecules is less than that of liquid molecules and the number of liquid molecules is less than that of solid molecules, so the distance between gas molecules is longer and the gravitation is less than that of others, and liquid take the second place The macroscopical appearance caused by these microcosmic differences are The solid has definite volume and shape The liquid has definite volume but have indefinite shape The gas has neither definite volume nor definite shape

9 But these three basic properties of materials expressing in gas, liquid and solid have difference in quantity and quality. In the same volume the number of gas molecules is less than that of liquid molecules and the number of liquid molecules is less than that of solid molecules, so the distance between gas molecules is longer and the gravitation is less than that of others, and liquid take the second place. The macroscopical appearance caused by these microcosmic differences are ： The solid has definite volume and shape. The liquid has definite volume but have indefinite shape. The gas has neither definite volume nor definite shape

流你及其物质 不过这三个物质基本属性表现在气体、液体 与固体方面却有量与质的差别。同样体积内的 分子数目,气体少于液体,液体又少于固体,因 此气体分子间距离大,引力小,液体次之。 这些微观的差异导致宏观表象是 固体有一定的体积和一定的形状; 液体有一定的体积而无一定的形状; 气体既无一定的体积也无一定的形状。 10

10 不过这三个物质基本属性表现在气体、液体 与固体方面却有量与质的差别 。同样体积内的 分子数目，气体少于液体,液体又少于固体，因 此气体分子间距离大，引力小，液体次之。 这些微观的差异导致宏观表象是： 固体有一定的体积和一定的形状； 液体有一定的体积而无一定的形状； 气体既无一定的体积也无一定的形状