水管工人玩过吧，我每次玩的时候都手忙脚乱的，就写了一个程序自动玩，效果不错。-plumber played before, I play every time when they are running around in circles, wrote an automatic play, and effectiveness.

精准的水力计算公式，可以准确的计算出水管的雷诺数、阻力系数(Accurate hydraulic calculation formula can accurately calculate the Reynolds number and drag coefficient of the outlet pipe)