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8 }% x/ [* p" P9 D- r% K; x
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these equations, as follows: - Invoke three fundamental physical principles that are deeply entrenched in our macroscopic observations of nature, namely,( G0 ?7 \6 f+ n1 `: ]
a. Mass is conserved (i.e., mass can be neither created nor destroyed).
+ R1 X7 j0 c }b. Newton’s second law: force = mass × acceleration.9 w" k, p% t! L! j0 E
c. 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.
$ q9 K$ w. z; s) z T1 ~这些方程如下:" _$ T7 {8 r! m- H& q- ~
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& N3 B" v- D0 U, P' I
1.质量是守恒的(即既不能产生质量也不能破坏质量)。0 v' Y, \! R, @2 ]
2.牛顿第二定律:力=质量×加速度。+ P4 |1 {9 ^! Z- ] d2 v. U! F
3.节约能源; 它只能从一种形式变为另一种形式。
" i5 @) a# S. s3 P2.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。) T, |% s) \& q1 e0 `& p" \, M
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。
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