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4. FLUlD DYNAMIC COEFFICIENTS
4.1 Hydrodynamic Coefficients of Hull
The hydrodynamic coefficients of the hull are defined as follows:
These coefficients are described using hydrodynamic derivatives as follows:
X'H=X'vvV'2+X'vvvvV'4+X'φφφ2
Y'H=Y'vV'+Y'vvvV'3+Y'φφ （6）
K'H=K'vV'+K'vvvV'3+K'φφ
N'H=N'vV'+N'vvvV'3+N'φφ
where v' is defined as follow:
The derivatives of the hull obtained by the towing tank tests are shown in Table 2 and the comparison of coefficients between measured and calculated by Equation (5) are shown in Figure 6.
Table 2 Hydrodymtnic derivatives of hull and coefficients of rudder
| Xvv' |
-0.0216 |
Kv' |
0.1591 |
| Xvvvv' |
0.0309 |
Kvvv' |
0.4644 |
| Xφφ' |
-0.0107 |
Kφ' |
-0.0161 |
| Yv' |
-0.2924 |
Nv' |
-0.1633 |
| Yvvv' |
-1.9134 |
Nvvv' |
0.0401 |
| Tφ' |
0.0212 |
Nφ' |
-0.0253 |
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| Cxδ |
-0.200 |
Ckδ |
0.270 |
| Cyδ |
-0.315 |
Cnδ |
0.174 |
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Fig.6 |
Variation of hydrodynamic coefficients of hull with leeway angle β (without rudder forces) |
4.2 Hydrodynamic Coefficients of Rudder
The hydrodynamic coefficients of the rudder force are expressed as
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