材料力学王洪伟.ppt

ENGINEERING FLUID MECHANICS School of Jet Propulsion 2012 Textbook: 《气体动力学基础》……王新月，陆利蓬 等 《Fluid Mechanics》……Frank M. White References: 《气体动力学基础》……潘锦珊等 Grades: Homework: 20% In class discuss quiz: 10% Midterm exam: 30% (Open books) Final exam: 40% (Close books) Schedule Chapter 1………Introduction (6 hours) Chapter 2………Fluid Statics (4 hours) Chapter 3………Integral Relations (12 hours) Midterm Exam (2 hours) Chapter 4………Differential Relations (12 hours) Chapter 5………Boundary Layer (6 hours) Final Exam 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 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 concept of a fluid A solid can resist a shear stress (剪切应力) by a static deformation. A fluid can not resist a shear stress by a static deformation. 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. History and Scope of Fluid Mechanics Pre-history: Sailing ships with oars(橹桨) and irrigation system were both known in prehistory Archimedes(285-212 BC) Parallelogram law for addition of vectors Law of buoyancy Leonardo da Vinci(1452-1519) Equation of conservation of mass in one-dimensional steady flow Experimentalist Turbulence Isaac Newton(1642-1727) 19th century Navier (1785-1836) Stokes (1819-1905) N-S equation §1.2 Some Properties of fluids (1) Viscosity(粘性) When a fluid is sheared（剪切）, it begins to move. Subsequently, a pair of forces appear on the shear surface, which resists the shear mot