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ITTC – Recommended
Procedures
Performance, Propulsion
1978 ITTC Performance Prediction
Method
7.5 – 02
03 – 01.4
Page 6 of 31
Effective Date
1999
Revision
00
for the delivered power.
Trial prediction with ∆C FC - ∆w C corrections
If CHOICE=1 the final trial predictions are
calculated as follows:
K
J
=
S
.
C
T
TS
2 2D
2
1
+ ∆C
( 1 − t)( − w + ∆w
) 2
With this K T /J² as input value, J TS and K QTS
are read off from the full scale propeller characteristics
and
n
P
T
DT
( 1 − w + ∆w
)
TS
FC
TS C
VS
= (r/s)
J . D
= 2
TS
K
5 3 QTS −3
π . ρ.
D . nT
. .10 (kW)
η
RM
Trial prediction with C NP correction
If CHOICE = 2 the shaft rate of rotation is predicted
on the basis of power identity as follows.
⎛ KQ
⎞
⎜
J ³
⎟
⎝ ⎠
T
1000. C
P
. PDS
=
3
2π
. ρ.
D²
V ( 1 − w )³
S
TS
C
2.5 Analysis of Speed Trial Results
The analysis of trials data is performed in a
way consistent with performance prediction but
starting P D and n backwards, i.e. from
K
Q
PD
=
2π
. ρ.
D
. n
. η
5 3 RM
.10³
J S is obtained from the full-scale open-water
characteristics K Q ≈ J S then
w
= 1 − J
. n.
D
T S
/
Further from K T ≈ J S characteristics
T = K
T
. ρ.
n²
D
( 1 − t)
T.
C T
=
1
. ρ.
V ². S
2
Then we obtain
∆ C = C − C
∆ w
FC
C
= w
2.6 Input Data
T
TS
4
− w
Input data sheets are given in ENCL.1
TS
T
V
K
Q0
J ³
⎛ K
=
⎜
⎝ J
Q
⎞
⎟
⎠
T
.η
RM
( 1 − w )/
J D
nS = VS
TS TS
.
n = C
T
NP
n
S
2.7 Output Data
- Output data I gives ITTC Standard Prediction
with C P = C N = 1.0, together with
model and full scale propulsive coefficients
(ENCL. 4).
- Output data II gives the final ship prediction
(ENCL. 5).