水流经变断面管道,已知小管径为d1,大管径为d2,d2/d1=2。试问哪个断面的雷诺数大?两端面雷诺数的比值Re1/Re2是多少?
参考答案:
解答过程略 答案为:Re1/Re2=2
()一个人,首先要看他的思想道德水平,其次再看他的文化和其他各方面的素质。
A.评论
B.评价
C.估计
D.评估
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