空气动力学三大方程
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7 }2 L0 f3 D4 r, H[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,+ T. h$ _0 t7 K. \
a. Mass is conserved (i.e., mass can be neither created nor destroyed).
/ P" k9 T* C1 g' _* M3 bb. Newton’s second law: force = mass × acceleration.
4 I! e4 _" F3 u' ^# xc. 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.3 U: I' k; v; N/ s( U+ K; |
这些方程如下:
- b) y/ ^3 {. _% N8 r6 W1.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: W9 P; |- O* G1 P# q( A
1.质量是守恒的(即既不能产生质量也不能破坏质量)。3 Y' z% _3 l( ~# c
2.牛顿第二定律:力=质量×加速度。
8 O* Y$ b5 Y4 \0 I3 y1 ` @$ ?, U3.节约能源; 它只能从一种形式变为另一种形式。
1 [" M; o4 K8 R7 P; q3 p2.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。) ^+ Y/ H3 f! P$ X8 ]+ T) V3 R
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。6 U4 ?( P' [" \3 w
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