空气动力学三大方程
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[color=rgba(0, 0, 0, 0.74902)]这里写自定义目录标题2 w! N' j7 W2 n8 B& A% T6 z+ g6 R* Y9 U
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these equations, as follows: - Invoke three fundamental physical principles that are deeply entrenched in our macroscopic observations of nature, namely,6 _" D' S+ {& G6 s- O- q
a. Mass is conserved (i.e., mass can be neither created nor destroyed).) h( K6 ^2 M i* q
b. Newton’s second law: force = mass × acceleration.
$ @, B1 o9 a. xc. Energy is conserved; it can only change from one form to another. - Determine a suitable model of the fluid. Remember that a fluid is a squishy substance, and therefore it is usually more difficult to describe than a well-defined solid body. Hence, we have to adopt a reasonable model of the fluid to which we can apply the fundamental principles stated in item 1.
- Apply the fundamental physical principles listed in item 1 to the model of the fluid determined in item 2 in order to obtain mathematical equations which properly describe the physics of the flow. In turn, use these fundamental equations to analyze any particular aerodynamic flow problem of interest./ q6 {# `) z: h- O A
这些方程如下:- o+ p# m6 }$ O* {& y7 a: y2 ?& i
1.引用我们对自然的宏观观察中根深蒂固的三个基本物理原则,即, i: u+ c" b0 E% G
1.质量是守恒的(即既不能产生质量也不能破坏质量)。) d& k# |% r8 y5 M, u& c8 l
2.牛顿第二定律:力=质量×加速度。
9 c# u6 T4 x. S2 u; Y3.节约能源; 它只能从一种形式变为另一种形式。
+ S y; F( Z5 M1 U' U2.确定合适的流体模型。 请记住,流体是一种柔软的物质,因此通常比明确定义的固体更难描述。 因此,我们必须采用合理的流体模型,我们可以应用第1项所述的基本原则。0 H- U1 `' J8 y5 a6 d
3.将第1项中列出的基本物理原理应用于第2项中确定的流体模型,以获得正确描述流动物理学的数学方程。 反过来,使用这些基本方程来分析任何感兴趣的特定空气动力学流动问题。$ n! N5 W1 Q1 F/ ]6 h3 f
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