文档介绍：CHAPTER 8 NORMAL SHOCK WAVES AND RELATED TOPICS
第八章正激波及有关问题
Shock wave: A large-pression wave, such as that produced by an explosion, caused by supersonic motion of a body in a medium. 激波是一个大振幅波,如由爆炸产生的波及物体在介质中超音速运动而引起的波.
INTRODUCTION
The purpose of this chapter and is to develop shock-wave theory, thus giving us the means to calculate the changes in the flow properties across a wave.
本章和第九章的目的是推导激波理论,因而得出计算通过激波的流动特性变化量的公式。
The focus of this chapter is on normal shock waves, as sketched in Fig. . The supersonic flow over a blunt body and the supersonic flow established inside a nozzle are shown in Fig. .
第八章的路线图:
正激波基本控制方程的推导
音速
能量方程的特殊形式
什么情况下流动是可压缩的?
用于计算通过正激波气体特性变化的方程的详细推导; 物理特性变化趋势的讨论
用皮托管测量可压缩流的流动速度
第八章路线图
THE BASIC NORMAL SHOCK EQUATIONS
正激波的基本方程
激波是很薄的、具有强粘性的区域。通过激波流动是绝热的但不等熵
Consider the rectangular control volume abcd given by the dashed line in . The shock wave is inside the control volume.
,激波在控制体内。
We apply the integral form of conservation equations to this control volume. 我们对这个控制体应用积分形式动量方程。
In the process, we observe four important physical facts about the flow given in Fig. : 在进行过程中,:
flow is steady, . ∂/∂t = 0. 流动是定常的。
flow is adiabatic: no heat is added or taken away from the control volume. 流动是绝热的,没有加入和带出控制体的热量。
are no viscous effects on the sides of the control volume.
控制体的边界上没有粘性的作用。
are no body forces; f=0。没有体积力。
连续方程:
()
()
动量方程:
()
x方向分量:
()
()
能量方程:
()
()
Repeating the above results for clarity, the basic normal shock equations are: 为了清晰起见,我们重复写出正激波基本方程:
连续:
动量:
能量:
焓:
状态方程:
()
()
()
Discussion: Finally, we note that Eqs. (),(),() are not limited to normal shock waves; they describe the changes that take place in any steady, adiabatic, inviscid flow where only one direction is involved. That is, in Fig. the flow is in the x direction only . This type of flow,