空气动力学三大方程7 _- u8 ?5 c& `
L x7 Z9 J( g: \% j) ^, P3 d[color=rgba(0, 0, 0, 0.74902)]这里写自定义目录标题1 p4 g# T* c1 c: \: Y/ ?+ P! t
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these equations, as follows: - Invoke three fundamental physical principles that are deeply entrenched in our macroscopic observations of nature, namely,
% l$ E$ g4 s2 o7 R* m0 C( n% Ia. Mass is conserved (i.e., mass can be neither created nor destroyed).9 `# `5 b: n9 c. Q' h3 T. K
b. Newton’s second law: force = mass × acceleration.3 E+ o. A5 g8 W v3 H3 } o! f' E
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.1 |9 ], \: o. j4 ~+ J
这些方程如下:8 J0 `6 b, Z4 ]
1.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
/ `/ ^3 }& i/ H8 W% v B, ?1 ]1.质量是守恒的(即既不能产生质量也不能破坏质量)。' N* n$ m! J) {
2.牛顿第二定律:力=质量×加速度。: R( z) m: x; b/ c( X& x5 M
3.节约能源; 它只能从一种形式变为另一种形式。! E. y4 {/ j% i8 g4 e9 M2 D9 d0 l
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。
9 ^6 t7 |8 E% V, t( 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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