Problem 4.134
[Difficulty: 3]
CS
(moves to
left at speed
V
c
)
y
x
c
d
R
x
V
j
+ V
c
V
j
+ V
c
t
R
Given:
Water jet striking moving cone
Find:
Thickness of jet sheet; Force needed to move cone
Solution:
Basic equations: Mass conservation; Momentum flux in x direction
Assumptions:
1) Steady flow
2) Incompressible flow 3) Atmospheric pressure in jet 4) Uniform flow 5) Jet relative velocity is
constant
Then
ρ
−
V
1
⋅
A
1
⋅
ρ
V
2
⋅
A
2
⋅
+
0
=
ρ
−
V
j
V
c
+
()
⋅
π
D
j
2
⋅
4
⋅
ρ
V
j
V
c
+
⋅
2
⋅
π
⋅
R
⋅
t
⋅
+
0
=
(Refer to sketch)
Hence
t
D
j
2
8R
⋅
=
t
1
8
4in
⋅
2
×
1
9in
⋅
×
=
t
0.222 in
⋅
=
Using relative velocities, x momentum is
R
x
u
1
ρ
−
V
1
⋅
A
1
⋅
⋅
u
2
ρ
V
2
⋅
A
2
⋅
This is the end of the preview. Sign up
to
access the rest of the document.
This note was uploaded on 10/19/2011 for the course EGN 3353C taught by Professor Lear during the Fall '07 term at University of Florida.
 Fall '07
 Lear
 Fluid Mechanics, Flux

Click to edit the document details