空气动力学三大方程
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9 ]3 g. v/ X- L" u4 z' h! [$ K[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,$ N2 K# o/ W# m4 H# N, Q6 V9 K
a. Mass is conserved (i.e., mass can be neither created nor destroyed)." g: o: D/ [; j. k* W2 M7 d
b. Newton’s second law: force = mass × acceleration.9 z: I( u" R: }1 O' X5 Y/ N
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.
0 Y, A$ A2 D9 i. F0 y% M这些方程如下:
6 g. U1 B9 }) i8 }* T6 ^9 S1.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
" ^( K, q8 O+ Q1.质量是守恒的(即既不能产生质量也不能破坏质量)。) K- w9 }7 j4 K7 U" _! K- T0 l* Y
2.牛顿第二定律:力=质量×加速度。9 [9 r3 g* b* R3 U. w
3.节约能源; 它只能从一种形式变为另一种形式。
* O5 B" l& A6 p4 {, b E2.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。' e$ `+ ] [- `
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。, G$ I$ e1 J, \2 d* i* A
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