如圖所示突然放大有壓管流,放大前細管直徑d1=100mm,放大后粗管直徑d2=200mm,若已知放大前斷面平均流速v1=4m/s,則局部水頭損失hn為()
A.0.256m B.0.347m C.0.612m D.0.459m
A.0.0261 B.0.0617 C.0.0452 D.0.0551
矩形斷面輸水明渠如圖所示,斷面尺寸為2m×1m,渠道的謝才系數(shù)C=48.5m1/2/s,輸水1000m長度后水頭損失為1m,則其沿程阻力系數(shù)λ應(yīng)為()
A.0.033 B.0.041 C.0.025 D.0.018