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
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; f, A( `8 R# J# h9 v/ pthese equations, as follows: - Invoke three fundamental physical principles that are deeply entrenched in our macroscopic observations of nature, namely,6 b6 j7 d& E. V! J3 w. M
a. Mass is conserved (i.e., mass can be neither created nor destroyed).2 j/ d2 m& b. L; e
b. Newton’s second law: force = mass × acceleration.# D0 J8 I5 t3 E- q, ]( ~
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.
3 ^5 e+ a' r* E2 J这些方程如下:0 ^8 t a/ H$ G3 L
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7 F c; q+ U* G9 Q4 }: o. W$ |
1.质量是守恒的(即既不能产生质量也不能破坏质量)。
& C" v' x+ e4 _; e g2.牛顿第二定律:力=质量×加速度。* O: P( X: v9 O; y0 m/ y
3.节约能源; 它只能从一种形式变为另一种形式。
5 d) r1 \1 U. s2.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。3 g& Z, o% L+ T0 O2 s
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。1 ~/ B3 v/ s3 k6 [
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