填空题

一条输水管,长l=1000m,管径d=0.3m,设计流量Q=0.055m3/s,水的运动黏度v=1×10-6m2/s,如果要求此管段的沿程水头损失为3m,试问应选择相对粗糙度为多少的管道()。

【参考答案】

53×10-3
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