Chapter 3 Fundamentals of Inviscid, incompressible Flow Theoretical fluid dynamics, being a difficult subject, is for convenience, commonly divided into two branches, one treating frictionless or perfect fluids, the other treating of viscous or imperfect fluids. The frictionles fluid has no existence in nature, but is hypothesized by mathematicians in order to facilitate the investigation of important laws and principles that may be approximately true of viscous or natural fluids

5.1 Introduction The properties of airfoils are the same as the properties of a wing with infinite span. However, all real airplanes have wings of finite span. In the present chapter, we will apply our knowledge of airfoil properties to the analysis for finite wings. As we have mentioned in the previous chapter, the analysis for the aerodynamics of wings is separated in two steps.now, we are going on the second-step in Prandtl's philosophy of wing theory

This chapter mainly deal with the properties of two-dimensional airfoils at mach number above 0.3 but below 1, where the compressibil ity must be considered

如上图所示的斜激波在真实情况下有时会碰到固壁或与其它激 波、膨胀波相交,进而发生相互作用,这种现象称为激波的干 扰与反射。本节的目的就是要定性地讨论激波的干扰问题

第八章我们讨论了正激波,本章我们讨论斜激波,及超音速流场中的另一个重要特征——膨胀波

一、能量方程的各种特殊表达形式 二、总温的计算公式 三、总压、总密度的计算公式 四、临界参数的定义与计算公式 五、特征马赫数(速度系数)M*的定义及计算公式

All real substances are compressible to some greater or lesser extend. When you squeeze or press on them, their density will change. This is particularly true of gases. (所有的真实物质都是可压缩的,当我们压挤 它们时,它们的密度会发生变化对于气体尤 其是这样)

\The compressibilty correction rule for thin wing The effect of compressibility in 3-D flows is somewhat less dramatic than with 2-D flows, but many of the same effects become important. Many of the same techniques for predicting linear compressibility effects work in 3-D too. For example

观察超音速下飞行器的升力、阻力的产生及绕飞行器流动的流场细节,包括激波、膨胀波的构型,可以采用以下两种方法: (1) Conduct flight tests using the actual vehicle 进行实际飞行器的飞行试验 (2) Run wind-tunnel tests on a small-scale modelof the vehicle 用飞行器的缩小模型进行风洞实验

0001下列泵中属于叶轮式泵的是 A.齿轮泵B.叶片泵 C.水环泵D.旋涡泵 0002不属于回转式容积式泵的是 A.水环泵B.齿轮泵C.螺杆泵D.旋涡泵 0003属于回转式容积泵的是 A.离心泵B.水环泵 C.旋涡泵D.轴流泵