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3. WAVE IMPACT SENSITIVITY ANALYSIS
A small tanker of data as in Tab. 1 is used as an input to the simulation experiment of wave actions due to the second order forces.
Table 1 Ship data
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L[m] = 97.4 cB[-] = 0.76
B[m] = 16.6 D[m] = 4.1
T[m] = 7.1 P/D[-] = 0.87
H[m] = 9.4 n[1/s] = 2.35
m[t] = 8950 m11 = k11m = 0.06m
Jz[tm2] = 5.2・106 m22 = k22m = 1.00m
AR[m2] = 12.3 m66 = k66Jz = 0.83Jz
λR[-] = 1.5 cm[-] = 0.8
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The most essential details of the ship manoeuvring mathematical model (4) constituting a basis for the simulation are presented below, which could effect the interpretation (validity) of the simulation output.
Rudder forces:
MzR = FyRxR (19)
vRy = c2(vy + ωzxR) (22)
Hull forces:
tgβ = -vy/vx, β∈<-180°,+180°> (25)
The rudder lift and drag coefficients as functions of the rudder incidence angle and propeller thrust load are taken from [1] and shown in Figs. 1 and 2.
Fig.1 |
Rudder lift coefficient as function of propeller thrust load coefficient. |
Fig.2 |
Rudder drag coefficient as function of propeller thrust load coefficient. |
The coefficient of hull surge force (ship resistance) cfxh is calculated according to:
cfxh = cfxho・cosβ・(1 - Ωm2 (27)
where cfxho is the resistance coefficient (negative) in a straight ahead motion.
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