空气动力学三大方程2 X k/ d7 {. P9 Z
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[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,
( a9 [5 T4 q( G% k- H+ na. Mass is conserved (i.e., mass can be neither created nor destroyed).
8 [. ^# P9 f% _! }( J4 X( Lb. Newton’s second law: force = mass × acceleration.5 ]8 ]1 U. {; R! x
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.# h6 M4 g' b3 V
这些方程如下:
" m" G. V/ D$ q* S, G% i2 p1.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 n' ^, A3 m' Z9 B" X; ]
1.质量是守恒的(即既不能产生质量也不能破坏质量)。
/ n7 j: `) f: D' \1 D7 {2.牛顿第二定律:力=质量×加速度。2 ~! k' ^, l% G: |
3.节约能源; 它只能从一种形式变为另一种形式。. I5 F; U+ d$ [
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。
+ p3 e; _4 _4 ^/ `/ H; [7 k3.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。) l- C! d# O9 \. L* i
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