空气动力学三大方程9 }6 n0 p3 A+ h2 V @- H- [. b
& v5 {$ D" Y( a6 m5 R" C# _[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,; l0 q/ U; O v- z5 K2 A3 ^
a. Mass is conserved (i.e., mass can be neither created nor destroyed).; P. r$ L1 o2 ^# i
b. Newton’s second law: force = mass × acceleration.5 G* D+ `$ K! P4 @% a9 v3 K
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.
9 S& W% y n6 S6 |/ Y这些方程如下:
( x v8 k+ U; C; 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
1 x' X5 G. a) \, J6 N: S. ~- T1.质量是守恒的(即既不能产生质量也不能破坏质量)。8 H* l! C2 E, s2 f! t
2.牛顿第二定律:力=质量×加速度。
( ~$ o, ^( W# Z1 J- h3.节约能源; 它只能从一种形式变为另一种形式。
- [, P% ~0 K' u' Z/ f! Q2.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。
! _) h+ J- y6 t+ S3 p) 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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