压强与流速的关系计算

p = p0(1-v^2/a0^2)^1/2        (1)

式中： p0 _ 无流压强，p -- 压强，V _ 流速, α0 _ 无流声速

1标准大气压＝101325牛顿／㎡

声速，空气（15℃）340m/s

压强与流速的关系，做泰勒展开，取前两项，就是伯努里方程: 

(1/2)*V^2 +(p/ p0)* a0^2= a0^2     (2)

设流速5m/s,算出p=101303牛顿／㎡,压强差p0- p=22牛顿／㎡

两个公式算出的结果对照如下：

V = 0, 0.1 a0 ,0.2 a0 ,0.3 a0,0.4 a0,0.5 a0,...

P = p0 , 0.995 p0  ,0.980 p0  ,0.954 p0 ,0.917 p0 ,0.866 p0 ,...

P = p0  ,0.995 p0 ,0.980 p0  0.955 p0 ,0.920 p0 ,0.875 p0 ,...

p0 - p = 0 ,0.005 p0  ,0.020 p0 ,0.046 p0 ,0.083 p0 ,0.134 p0 ,...

p0 - p = 0,0.005 p0  ,0.020 p0 , 0.04 5 p0 ,0.080 p0 ,0.125 p0 ,...

中学流体知识，只定性不定量的历史，应结束。