空气动力学三大方程
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4 h+ J6 v/ @, B$ _[color=rgba(0, 0, 0, 0.74902)]这里写自定义目录标题
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these equations, as follows: - Invoke three fundamental physical principles that are deeply entrenched in our macroscopic observations of nature, namely,
- ~0 J5 J- f! b6 w) S; ya. Mass is conserved (i.e., mass can be neither created nor destroyed).5 e4 K0 P; i" d- @/ o4 M) Q
b. Newton’s second law: force = mass × acceleration.
7 ~; j$ J7 q" [" U8 \9 u' Ec. 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.
+ o7 \1 G; `, W. ], U$ \0 L这些方程如下:
7 M. M# O' S# A/ [9 j/ _5 ?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 P' k; j0 c, X q+ x- n
1.质量是守恒的(即既不能产生质量也不能破坏质量)。. r1 S2 ]) N7 Z# Y" B! i/ h
2.牛顿第二定律:力=质量×加速度。
4 L, g. G2 Z, g- V6 C3.节约能源; 它只能从一种形式变为另一种形式。
* p2 X: t+ ~8 h5 J* O2.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。- c- ~) g9 E3 a7 X& [
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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