空气动力学三大方程$ o0 I7 W, X! I; V2 h
H* B) l3 y& g$ u T5 }[color=rgba(0, 0, 0, 0.74902)]这里写自定义目录标题
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% a- X, j; q" ]+ [( K9 B* ethese equations, as follows: - Invoke three fundamental physical principles that are deeply entrenched in our macroscopic observations of nature, namely,
2 ^; f# U' `9 V( M8 y+ T4 |a. Mass is conserved (i.e., mass can be neither created nor destroyed).
; C' |, C' l: G; z6 Zb. Newton’s second law: force = mass × acceleration.
% d7 D; z8 b. I$ Tc. 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.
; L% X' s( h0 u; D/ p1 c; U这些方程如下:
5 X# Q7 A7 K9 V9 I1.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) I8 A- u: p1.质量是守恒的(即既不能产生质量也不能破坏质量)。# @1 W# y8 s* r. E
2.牛顿第二定律:力=质量×加速度。+ q1 m4 w ?8 }+ e
3.节约能源; 它只能从一种形式变为另一种形式。, p3 N# S% `/ ]& Y; ^0 }
2.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。! W: N+ |" O2 d& L% g# U8 p2 g7 \7 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。
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