第一章 2012 王洪伟课件.pptVIP

ENGINEERING FLUID MECHANICS;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); ; Chapter 1 Introduction ;Curved shoot (Banana shoot);Jupiter;How can an airplane fly?;A turbofan(涡扇) jet engine;What is Fluid Mechanics ?;The concept of a fluid;History and Scope of Fluid Mechanics;Archimedes(285-212 BC);Leonardo da Vinci(1452-1519);Isaac Newton(1642-1727);18th century;19th century;20th century;§1.2 Some Properties of fluids;Velocity gradient;(2) Compressibility(压缩性);(4) Thermal Conductivity (热传导);§1.3 The Fluid as a Continuum (连续介质）;Such a fluid is called a continuum, Which simply means the differential calculus can be used to analyze the substance.;§1.4 Surface force(表面力) and body force（质量力，体积力）;§1.5 Two different points of view in analyzing problems in mechanics;Flow classification (流动分类);One Two dimensional Three;A pathline is the actual path traversed by a given fluid particles.;; Stream surface(流面), Streamtube (流管), Flow pattern(流型);Flow field (流场) ： In a given flow situation, the properties of the fluid are functions of position and time, namely space-time distributions of the fluid properties. ; Streamline equation(流线方程);Example:;Direction: u=kx, v=-ky Quadrant I （第一象限) (x0,y0); u0, v0 ;Homework 1.1 Given the velocity distribution: u = - c y, v = c x , w = 0 Where c is a positive constant. Compute and plot the streamlines of the flow. 1.2 Given velocity distribution: u = x + t , v = - y + t , w = 0 ( t is time) Find the streamline passing through point(-1,-1) at the instant t=0. 思考题： 草坪旋转喷头出来螺旋水流，是迹线还是流线？