空气动力学三大方程
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# e/ ?0 s* {' L- ?. I" G[color=rgba(0, 0, 0, 0.74902)]这里写自定义目录标题
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( j5 q* Z; \ Rthese equations, as follows: - Invoke three fundamental physical principles that are deeply entrenched in our macroscopic observations of nature, namely,
5 Z/ Y1 d. c3 za. Mass is conserved (i.e., mass can be neither created nor destroyed).0 ]3 \, B4 [6 a6 B u% D1 E, a2 U
b. Newton’s second law: force = mass × acceleration., ]& F" c/ G; I- Y4 L, l/ @
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.. ~2 Y7 m% x( v$ l& E) i+ E
这些方程如下:
! B% k$ N8 V& r1.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8 B2 z5 q) O4 y6 q4 ?$ r
1.质量是守恒的(即既不能产生质量也不能破坏质量)。
6 x' }: W* z. ~+ W* w2.牛顿第二定律:力=质量×加速度。1 W7 L2 P! T& C; C! n* U
3.节约能源; 它只能从一种形式变为另一种形式。
" G1 T( E6 D! p% j+ j C2.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。
/ P& t, \4 q U8 C. j3.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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