北京航空航天大学：《工程流体力学》课程PPT教学课件（双语版）Chapter 1 Fluid Mechanics Introduction

ELUT MECHANICS School of Jet Propulsion Beihang university 2021/2/22

2021/2/22 1 School of Jet Propulsion Beihang University

Chapter l Introduction 1.1 Preliminary Remarks When you think about it, almost everything on this planet either is a fluid or moves within or near a fluid. Frank M. White What is a fluid? 23 2021/2/22

2021/2/22 2 Chapter 1 Introduction 1.1 Preliminary Remarks When you think about it, almost everything on this planet either is a fluid or moves within or near a fluid. -Frank M. White What is a fluid?

The concept of a fluid A solid can resist a shear stress(剪切应力) by a static deformation a fluid can not Any shear stress applied to a fluid, no matter how small, will result in motion of that fluid The fluid moves and deforms continuously as long as the shear is applied 2021/2/22

2021/2/22 3 The concept of a fluid A solid can resist a shear stress(剪切应力) by a static deformation, a fluid can not. Any shear stress applied to a fluid, no matter how small, will result in motion of that fluid. The fluid moves and deforms continuously as long as the shear is applied

What is fluid mechanics Fluid mechanics is the study of fluid either in motion( Fluid Dynamics流体动力学)orat rest( Fluid statics流体静力学)qnd subsequent effects of the fluid upon the boundaries, which may be either solid surfaces or interfaces with other fluids 2021/2/22

2021/2/22 4 What is Fluid Mechanics Fluid Mechanics is the study of fluid either in motion (Fluid Dynamics 流体动力学) or at rest(Fluid Statics 流体静力学) and subsequent effects of the fluid upon the boundaries, which may be either solid surfaces or interfaces with other fluids

The famous collapse of the Tacoma Narrow Bridge in 1940 Curved shoot( Banana shoot) Jospin Spin 2021/2/22 5

2021/2/22 5 The famous collapse of the Tacoma Narrow Bridge in 1940 Curved shoot (Banana shoot) Nospin Spin why

Boeing 747 An-225 70.7×64.4×19.41(m) 84×884×18.1(m) 395000kg 600000kg How can the airplane fly? D Drag &Lift 2021/2/22 6

2021/2/22 6 Boeing 747 70.7×64.4×19.41 (m) 395 000kg An-225 84×88.4×18.1 (m) 600,000kg How can the airplane fly? Drag & Lift

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The engine of a turbofan(涡扇)jet N 2021/2/22 8

2021/2/22 8 The engine of a turbofan(涡扇) jet

cfm CFM56-7 DAC nemabonal MODULAR DESIGN " MODULE ①

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History and Scope of Fluid mechantics Pre-history Sailing ships with oars(橹桨) and irrigation system were both known in prehistory r“ 2021/2/22 10

2021/2/22 10 History and Scope of Fluid Mechanics Pre-history: Sailing ships with oars(橹桨) and irrigation system were both known in prehistory