Civil Engineering Reference
In-Depth Information
g
c
HH fffV VD
)
+
(
)
=
(
(
)
+
(
)
cVV
+−
:
−
∆
/
2
0
,, ..
(6.20)
p
Le
p
Le
Le
Le
)
+
g
c
HH ffVV D
(
(
)
+
(
)
=
(
)
cVV
−−
:
−
∆
/
2
0
,, ..
(6.21)
p
Ri
p
Ri
Ri
Ri
Solving these equations produced a theoretical result that usually corresponds
quite closely to actual system measurements (if the data and assumptions used to build
the numerical model are valid). Transient analysis results that are not comparable with
actual system measurements are generally caused by inappropriate system data (espe-
cially boundary conditions) and inappropriate assumptions. The MOC is based on a
finite difference technique where pressures are computed along the pipe for each time
step [7-8]:
1
2
C
g
VV HH
c
∆
t
D
VV VV
(
(
)
(
)
+
(
)
−
H
=
−
+
f
−
,
(6.22)
p
Le
ri
Le
ri
Le e
ri
ri
g
2
1
2
)
+
g
c
HH f
)
−
∆
t
D
VV VV
(
(
)
(
(
V
=
V
−
V
−
−
,
(6.23)
p
Le
ri
Le
ri
Le e
ri
ri
2
f = friction, C = slope (deg.), V = velocity, t = time, H = head (m)
6.3 results And discussion
Water hammer pressure or surge pressure (ΔH) is a function of independent variables
(X) such as: ΔH ≈ ρ, C1, Ep, E w, V, T, C, g, Tp f, g, D, L. Hence, this chapter cali-
brated and validated numerical simulations for three parameter: p = f (V, T, L). Input
data were in relation to water hammer condition.
tABle 6.1
Model Summary and Parameter Estimates (Water hammer condition).
Model
Un-standardized Coefficients
Standardized Coefficients
t
Sig.
B
Std. Error
Beta
1
(Constant)
28.762
29.730
.967
.346
flow
.031
.010
.399
2.944
.009
distance
-.005
.001
-.588
-4.356
.000
time
.731
.464
.117
1.574
.133
2
(Constant)
14.265
29.344
.486
.632
flow
.036
.010
.469
3.533
.002
distance
-.004
.001
-.520
-3.918
.001
3
(Constant)
97.523
1.519
64.189
.000
4
(Constant)
117.759
2.114
55.697
.000
distance
-.008
.001
-.913
-10.033
.000
Search WWH ::
Custom Search