Civil Engineering Reference
In-Depth Information
ˆ
{ }
fS f
⋅
Af
⋅
n
nn
nuvw
,,
=
where
=
(3.25)
2
(
)
5 / 3
σ
ˆ
11.5
+⋅
Af
⋅
n
nn
and where
ˆ
=⋅
, and
x
f
L
is the integral length scale of the relevant turbu-
lence component, as defined in Eq. 3.24 above.
x
f
f
f
LV
/
n
n
Fig. 3.5
Kaimal auto spectra of turbulence components
Unless full scale recordings indicate otherwise, the following values of the parameter
A
may be adopted:
= = =
. With these parameters, Eq. 3.25 has
been plotted in Fig. 3.5. Alternatively, the von Kármán [11] spectra
A
6.8 ,
A
A
9.4
u
v
w
ˆ
{ }
fS f
⋅
4
f
⋅
u
u
=
(3.26)
2
(
)
5 / 6
σ
ˆ
2
1
+
70.8
⋅
f
u
u
