问答题
(清华大学2006--2007学年春季学期期中考试试题)A fireboat-pump delivers water to a vertical nozzle with a 3：1 diameter ratio，as in Fig．6-38．If friction is neglected and the flow rate is 0．02 m
3
／s，how high will the outlet water jet rise?
【正确答案】正确答案：由题意知，根据质量守恒得：
或者： h=△h+h"=12．9+0．7+1．2=14．8(m) [6—129] (清华大学2006--2007学年春季学期期中考试试题)Consider incompressible flow in the entrance of a circular tube，as in Fig．6-39．The inlet flow is uniform，u
1
=U
0
．The flow at section 2 is developed pipe flow．Find the wall drag force F as a function of(p
1
，p
2
，ρ，U
o
，R)if the flow at section 2 is：
或者： h=△h+h"=12．9+0．7+1．2=14．8(m) [6—129] (清华大学2006--2007学年春季学期期中考试试题)Consider incompressible flow in the entrance of a circular tube，as in Fig．6-39．The inlet flow is uniform，u
1
=U
0
．The flow at section 2 is developed pipe flow．Find the wall drag force F as a function of(p
1
，p
2
，ρ，U
o
，R)if the flow at section 2 is：
【答案解析】