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equations in first order form appear as
z
r =
Az
+
P
with z and P the same as in Eq. (13.73) and
.
.
.
0
1
0
0
··················
··················
···
······
.
.
.
)
∂φ
r 2
(ν/
ν/
r
0
1
/
K
2
··················
··················
···
······
K (1 ν
2 .
.
.
2 )
4
∂φ
2
∂φ
2(1
ν
)
A
=
(13.74)
r 4
4
r 4
2 )
K ( 3 2 ν ν
2
∂φ
2
∂φ
)
1
/
r
(ν/
r
n φ
+
t 2 .
.
.
r 3
2
2
2
r 2 ∂φ
∂φ
+ ρ
1
+
k
··················
··················
···
······
.
.
.
2 )
K (1 ν
n r +
2 )
K (3 2 ν ν
2
∂φ
r 2
1
(
1
ν)/
r
r 3
2
.
.
.
2
∂φ
2 K (1 ν )
r 2
2
Reduction to Ordinary Differential Equations
The
derivatives can be eliminated in Eqs. (13.73) and (13.74) by expanding the variables
in a Fourier series
φ
w(
φ)
w
c m
(
)
w
s m
(
)
r,
r
r
=
θ(
φ)
θ
m
(
)
θ
m
(
)
r,
r
r
z
=
cos m
φ +
sin m
φ
(13.75)
V
(
r,
φ)
V m (
r
)
V m (
r
)
m
=
0
m r (
r,
φ)
m c m (
r
)
m s m (
r
)
The loading p z (
r,
φ)
should also be expanded in a Fourier series
p c m (
φ
p s m (
p z (
r,
φ) =
r
)
cos m
φ +
r
)
sin m
(13.76)
m
=
0
Multiply both sides of Eq. (13.76) by cos n
φ
and integrate from
φ =
0to
φ =
2
π
, i.e.,
2 π
2 π
2 π
p c m (
p s m (
p z (
r,
φ)
cos n
φ
d
φ =
r
)
cos m
φ
cos n
φ
d
φ +
r
)
sin m
φ
cos n
φ
d
φ
0
0
0
m
=
0
Since
2 π
2 π
2
π
m
=
n
=
0
cos m
φ
cos n
φ
d
φ =
π
m
=
n
and
sin m
φ
cos n
φ
d
φ =
0
0
0
m
=
n
0
it follows that
2 π
1
2
p 0 (
r
) =
p z (
r,
φ)
d
φ
(13.77a)
π
0
2 π
1
π
p c m (
r
) =
p z (
r,
φ)
cos m
φ
d
φ
m
>
0
(13.77b)
0
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