本书作为工科学生流体力学基础课程的双语教材，内容包括流体力学的基本原理和方程。该书各章节都配有丰富的案例详解、习题及相关知识在工程中的应用案例分析和研究，尤其增加了关于流体传动装置、液压系统及元件的实例分析，可使读者认识并理解如何将流体力学知识应用于工程实践。本书共六章，包括流体的基本性质，流体静力学，流体运动基本内容，流体动力学基本方程及其应用，量纲分析和相似原理，黏性不可压缩流体在孔口、狭缝中的内部流动（泵-涡轮系统的能量方程分析及应用，流体传动系统功率和效率的计算等）。
本书可作为普通高等学校工科各专业，特别是机械类相关专业流体力学课程双语教学教材，也可供相关专业的工程技术人员参考。

This book is a bilingual textbook for engineering students on the fundamentals of fluid mechanics, covering fundamental principles and equations of fluid mechanics. Readers will understand how to apply the knowledge of fluid mechanics to the engineering practices through abundant examples and application case analysis and studies, especially on analysis of fluid transmission devices, hydraulic systems and elements. The book consists of six chapters, including fluid properties, fluid statics, basics of fluid kinematics, fundamental equations of fluid dynamics and their application, dimensional analysis and similarity, internal flow of viscous incompressible fluid in orifices and narrow gaps, energy equation and its application to systems involving pump and turbine, calculations of the power and efficiency of fluid transmission systems. The analysis of some problems and derivation of formulas are appropriately simplified in this book, and there are abundant exercises in each chapter.
This book is written as a text book for the course in fluid mechanics for engineering students of colleges and universities, especially for students of mechanical engineering. The book can also be used as reference for engineers and technicians.

该书各章节都配有丰富的案例详解、习题及相关知识在工程中的应用案例分析和研究，尤其增加了关于流体传动装置、液压系统及元件的实例分析，可使读者认识并理解如何将流体力学知识应用于工程实践。
本书可作为普通高等学校工科各专业，特别是机械类相关专业流体力学课程双语教学教材，也可供相关专业的工程技术人员参考。

工程流体力学是工科相关专业的重要基础课程。本书为适用于单学期30 ~ 40课时双语教学及境内、境外本科生共同学习使用的简明教材。
本书内容共六章，着重讲述流体力学的基础原理和基础假设，以及怎样应用这些基本原理来解决实际的工程问题。第1章介绍流体力学的基本研究内容、压强的表示方法及流体的基本性质，包括流体的密度、黏度、表面张力等；第2章为流体静力学相关内容，包括流体上的力，流体静压强分布，测压管的原理与应用，平面壁和曲面壁上的流体静压力以及流体的相对静止等；第3章介绍描述流体运动的方法和相关概念，如流线、系统和控制体，以及如何应用雷诺输运定理将物理关系在系统和控制体间转换；第4章介绍理想流体动力学的基础方程，包括连续性方程、伯努利方程及其应用和动量方程；第5章介绍量纲分析和相似原理的基本思想及其在设计和简化实验系统、分析实验数据方面的优势；第6章为黏性不可压缩流体的内部流动，主要介绍实际流体的能量损失和层流及紊流状态，其中还简单分析了黏性流体在圆管、孔口和缝隙中的流动特点。
本书对一些问题的分析和公式推导做了适当简化，增加了很多关于流体传动、液压泵、阀及液压系统的案例分析和例题。特别在第6章关于实际流体的能量方程部分，重点增加了包括泵和涡轮系统的能量方程及系统功率、效率的计算，通过这些内容向读者展示作为机械工程师可能处理的与流体相关的问题和应用。通过本课程的学习，对简单的工程问题，读者应该能够独立对待解决的问题进行分析，做出适当的假设或近似，然后运用相关的定理建立控制方程并求解，后代入数据进行计算。
本书的编者感谢华侨大学教材建设项目的支持和教学团队各位教师的通力协作。本书由刘晓梅任主编，李洪友、林添良任副主编。编写团队其他成员包括
闫洁、刘晶峰、顾永华、段闯闯。
本书可作为高等院校相关专业流体力学的教材，特别适用于机械工程类专业，也可供工程技术人员参考。
由于作者水平有限，书中难免有不妥之处，恳请读者批评指正。

Preface
Engineering fluid mechanics is an important basic course for related majors. This is a brief bilingual course matching with one-semester 30~40 class hours for both domestic and overseas under-graduates.
In this book of six chapters, we stress the governing principles, the assumptions and the method to apply the principles to the solution of practical engineering problems. In chapter 1, some fundamental aspects of fluid mechanics, pressure scales and fluid properties are introduced, including density, viscosity and surface tension. Chapter 2 introduces fluid statics, including forces on fluid, distribution of pressure in fluid at absolute and relative rest, theories and applications of manometer, hydrostatic force on a plane surface and a curved surface etc. Chapter 3 explains methods and concepts for the description of fluid motion, including streamline, system and control volume, and Reynolds transport theorem for the transformation from system to control volume. Emphasis is placed on the fundamental equations of ideal fluid dynamics in chapter 4, including the equation of continuity, the Bernoulli equation and the equation of momentum. The advantages of using dimensional analysis and similarity for planning and simplifying experiments and for organizing test data are featured in Chapter 5. Chapter 6 expands on the internal flow of viscous incompressible fluid, includes energy losses of viscous fluid flow, the flow regimes of laminar and turbulent, practical concerns such as pipe flow, orifice and nozzle flow, and narrow gap flow are also discussed in this chapter.
The analysis of some problems and derivation of formulas are appropriately simplified in this book, and there are abundant examples and exercises of fluid transmission, hydraulic pump and valves. Special attention are given to the energy equation of real fluid, calculation of power and efficiency for the systems involving pump and turbine are presented so that the readers can understand and analyze many of the practical problems encountered by the engineer. Through this course, readers should be able to analyze problems independently, make assumptions, establish equilibrium equations, substitute parameters and solve simple engineering problems by using relevant principles.
The authors are very much indebted to the textbook funding project of Huaqiao University. This book is edited by Liu Xiaomei, Li Hongyou and Lin Tianliang. Thanks to Yan Jie,

CONTENTS/目录
Preface
Nomenclature 001
CHAPTER 1
BASIC CONSIDERATIONS 002
1.1?Introduction 002
1.2?Hypothesis of continuum model 004
1.3?Pressure scales 008
1.4?Fluid Properties 010
1.5?Forces on a Fluid 038
Exercises 1 040
CHAPTER 2
FLUID STATICS 052
2.1?Introduction 052
2.2?Pressure at a point 054
2.3?Pressure Variation in a Fluid at rest 054
2.4?Manometers 062
2.5　Forces on Plane Surfaces 074
2.6　Forces on Curved Surfaces 092
2.7　Fluid at Relative Rest 100
Exercises 2 112
CHAPTER 3
BASICS OF FLUID KINEMATIC 128
3.1　Description of Fluid Motion 128
3.2　Classification of Fluid Flows 136
3.3　Related Concepts of Fluid Flow 142
Exercises 3 156
CHAPTER 4
BASICS OF FLUID DYNAMICS 160
4.1　Basic Conservation Laws 160
4.2　Equation of Continuity 162
4.3　The Bernoulli Equation 178
4.4?Applications of the Bernoulli Equation 198
4.5?The Momentum Equation 214
Exercises 4 244
CHAPTER 5
DIMENSIONAL ANALYSIS AND
SIMILARITY 260
5.1?Introduction 260
5.2?Dimensional Analysis 260
5.3?Similarity 274
Exercises 5 282
CHAPTER 6
INTERNAL FLOW FOR VISCOUS INCOMPRESSIBLE FLUID 288
6.1?Bernoulli Equation for Viscous Incompressible Flow 288
6.2?Laminar and Turbulent Flows of Viscous Incompressible Fluid 300
6.3?Laminar Flow in Pipes 306
6.4?Turbulent Flow in Circular Pipe 324
6.5?Flow at Orifices, Tubes and Slender Holes 340
6.6?Developed Flow in Gaps 348
Exercises 6 358
Appendix A　ANSWERS 370
Appendix B　The moody chart 372
BIBLIOGRAPHY 373
前言
常用符号表 001
第1章
基础知识 003
1.1　引言 003
1.2　连续介质假设 005
1.3　压强的表示方法 009
1.4　流体的性质 011
1.5　流体受的力 039
习题一 041
第2章
流体静力学 053
2.1　引言 053
2.2　静止流体内一点的压强 053
2.3　静止流体内的压强分布 055
2.4　测压管 063
2.5　平面壁上的流体静压力 075
2.6　曲面壁上的流体静压力 093
2.7　流体的相对静止 101
习题二 113
第3章
流体运动基础 129
3.1　描述流体运动的方法 129
3.2　流动的分类 137
3.3　流体运动相关概念 143
习题三 157
第4章
流体动力学基础 161
4.1　基本守恒定律 161
4.2　连续性方程 163
4.3　伯努利方程 179
4.4　伯努利方程的应用 199
4.5　动量方程 215
习题四 245
第5章
量纲分析和相似原理 261
5.1　引言 261
5.2　量纲分析 261
5.3　相似原理 275
习题五 283
第6章
黏性不可压缩流体的内部流动 289
6.1　黏性不可压缩流动的伯努利方程 289
6.2　黏性不可压缩流体的层流和紊流 301
6.3　圆管层流 307
6.4　圆管紊流 325
6.5　孔口、管口和细长管出流 341
6.6　缝隙出流 349
习题六 359
附录A　习题答案 370
附录B　莫迪图 372
参考文献 374