空气动力学三大方程
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[color=rgba(0, 0, 0, 0.74902)]这里写自定义目录标题6 L3 K2 F( p1 Z( E8 x x) L
' o% ?# m8 ?( W" Nthese equations, as follows: - Invoke three fundamental physical principles that are deeply entrenched in our macroscopic observations of nature, namely,0 v# W) w7 D5 g6 r" s7 m
a. Mass is conserved (i.e., mass can be neither created nor destroyed).
: x. L& N% u! P9 Yb. Newton’s second law: force = mass × acceleration.
P! H0 [9 C3 S' u ac. 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 W/ Z8 n, o' F: |
这些方程如下:3 {7 |- L4 |/ S+ j
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
, Y4 q. R" v& C: o1.质量是守恒的(即既不能产生质量也不能破坏质量)。
& _; _7 E: h- R# R& p6 `5 _2.牛顿第二定律:力=质量×加速度。' Z2 L! \5 C( t" J7 k
3.节约能源; 它只能从一种形式变为另一种形式。
* p, Q9 q1 y. t* T& o2.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。
1 g! A- V% _+ W U" V. f$ A3.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。) ], j( ]2 d( R/ `
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