空气动力学三大方程
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! i5 n+ X* f: N# T' r[color=rgba(0, 0, 0, 0.74902)]这里写自定义目录标题5 N" ]# w D& z7 L4 K, c* l
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these equations, as follows: - Invoke three fundamental physical principles that are deeply entrenched in our macroscopic observations of nature, namely,) U/ g8 m' b& q% a0 P1 j" W
a. Mass is conserved (i.e., mass can be neither created nor destroyed).
9 j$ v( i# B. Fb. Newton’s second law: force = mass × acceleration.
' M2 ?8 t0 s0 h+ `0 D/ Ic. 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.
: q) o2 Z4 b$ i( I- J# S这些方程如下:/ [7 i' n7 {/ T0 Z
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& B# |$ b: j5 x+ A" ^
1.质量是守恒的(即既不能产生质量也不能破坏质量)。+ W4 W7 |/ M* s& m
2.牛顿第二定律:力=质量×加速度。1 U" f+ n# L- _% I9 X
3.节约能源; 它只能从一种形式变为另一种形式。$ \ g# O3 E& c% H( 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。
% h7 k& I4 @0 y1 H, ^ t* |4 _9 z4 D3.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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