A . 1
B . 2
C . 3
D . 4
[单选题]图示变直径管d1=100mm,d2=200mm,流速v2=1m/s则v1=()。A . 2m/sB . 3m/sC . 4m/sD . 8m/s
[单选题]某变径管的雷诺数之比Re1∶Re2=1∶4,则其管径之比d1∶d2,为()。A .1∶4B .1∶2C .2∶1D . D.4∶1
[单选题]恒定流变直径管,直径d1=320mm,d2=160mm,流速v1=5m/s,v2为()。A.3m/sB.4m/sC.6m/sD.9m/s
[单选题]已知d1=1OOmm,d2=200mm,v1=4m/s,管道突然扩大的水头损失为( )mH2O。A.0.77B.0.61C.0.46D.0.20
[单选题]已知d1=100mm,d2=200mm,v1=4m/s,管道突然扩大的水头损失为( )mH2O。A.0.77B.0.61C.0.46D.0.20
[单选题]一直径d1=0.2m的圆管,突然扩大到直径为d2=0.3m,若v1=9.55m/s,则v2与Q分别为( )。A.4.24m/s,0.3m3/sB.2
[单选题]一直径d1=0.2m的圆管,突然扩大到直径为d2=0.3m,若v1=9.55m/s,则v2与Q分别为( )。A.4.24m/s,0.3m3/sB.2
[单选题]一直径d1=0.2m的圆管,突然扩大到直径为d2=0.3m,若v1=9.55m/s,则v2与Q分别为( )。A.4.24m/s,0.3m3/sB.2
[单选题]一直径d1=0.2m的圆管,突然扩大到直径为d2=0.3m,若v1=9.55m/s,则v2与Q分别为( )。A.4.24m/s,0.3m3/sB.2
[单选题]一直径d1=0.2m的圆管,突然扩大到直径为d2=0.3m,若v1=9.55m/s,则v2与Q分别为( )。A.4.24m/s,0.3m3/sB.2