Ship acceleration motion under the action of a propulsion system: a combined empirical method for simulation and optimisation

Figures & data

Figure 1. A ship accelerating forward: (a) longitudinal view and (b) top view. The ship initially is at rest, and a thrust force, T₀, triggers the motion (right). Then, the speed of ship increases up to the time a dynamic equilibrium between all forces and moments is established (left). (c) shows some geometrical properties of the ship used for computation of the resistance.

Figure 2. Body line of the displacement hull, model INSEAN 2340, studied by Olivieri et al. (2003).

Table 1. Principal characteristics of the displacement hull, model INSEAN 2340, studied by Olivieri et al. (2001).

Parameter	Value
Scale factor	24.82
Length between perpendiculars (m)	5.72
Length at water level (m)	5.72
Beam (m)	0.76
Draft (m)	0.248
Trim angle (degrees)	0.00
Displacement (ton)	0.549
Volume (m^3)	0.549
Block coefficient	0.506
Prismatic coefficient	0.613
Midship section coefficient	0.825
Waterplane coefficient	0.778

Figure 3. Comparison of predicted resistance and experimental data of Olivieri et al. 2001 for the model with body lines of Figure 2 and principal characteristics of Table 1.

Figure 4. Comparison of predicted total resistance coefficient and experimental data of Olivieri et al. (2001) for the model with body lines of Figure 2 and principal characteristics of Table 1.

Figure 5. Sample of computed K_T and K_Q for B-Series propellers with A_E/A_o = 0.7: (a) Z = 3 and (b) Z = 4.

Table 2. Coefficients to be implemented in Equations (41) and (42).

KT						KQ
N	CN	SN	tN	uN	vN	N	CN	SN	tN	uN	vN
1	0.008805	0	0	0	0	1	0.0037937	0	0	0	0
2	−0.204554	1	0	0	0	2	0.0088652	2	0	0	0
3	0.166351	0	1	0	0	3	−0.032241	1	1	0	0
4	0.158114	0	2	0	0	4	0.0034478	0	2	0	0
5	−0.147581	2	0	1	0	5	−0.0408811	0	1	1	0
6	−0.481497	1	1	1	0	6	−0.108009	1	1	1	0
7	0.415437	0	2	1	0	7	−0.0885381	2	1	1	0
8	0.0144043	0	0	0	1	8	0.188561	0	2	1	0
9	−0.0530054	2	0	0	1	9	−0.0037087	1	0	0	1
10	0.0143481	0	1	0	1	10	0.005137	0	1	0	1
11	0.0606826	1	1	0	1	11	0.0209449	1	1	0	1
12	−0.0125894	0	0	1	0	12	0.0047432	2	1	0	1
13	0.0109689	1	0	1	0	13	−0.0072341	2	0	1	1
14	−0.133698	0	3	0	0	14	0.0043839	1	1	1	1
15	0.0063841	0	6	0	0	15	−0.0269403	0	2	1	1
16	−0.0013272	2	6	0	0	16	0.0558082	3	0	1	0
17	0.168496	3	0	1	0	17	0.0161886	0	3	1	0
18	−0.0507214	0	0	2	0	18	0.0031809	1	3	1	0
19	0.0854559	2	0	2	0	19	0.015896	0	0	2	0
20	−0.0504475	3	0	2	0	20	0.0471729	1	0	2	0
21	0.010465	1	6	2	0	21	0.0196283	3	0	2	0
22	−0.0064827	2	6	2	0	22	−0.0502782	0	1	2	0
23	−0.0084173	0	3	0	1	23	−0.030055	3	1	2	0
24	0.0168424	1	3	0	1	24	0.0417122	2	2	2	0
25	−0.001023	3	3	0	1	25	−0.0397722	0	3	2	0
26	−0.0317791	0	3	1	1	26	−0.0035002	0	6	2	0
27	0.018604	1	0	2	1	27	−0.0106854	3	0	0	1
28	−0.004108	0	2	2	1	28	0.001109	3	3	0	1
29	−0.0006068	0	0	0	2	29	−0.0003139	0	6	0	1
30	−0.0049819	1	0	0	2	30	0.0035985	3	0	1	1
31	0.0025983	2	0	0	2	31	−0.0014212	0	6	1	1
32	−0.0005605	3	0	0	2	32	−0.0038364	1	0	2	1
33	−0.0016365	1	2	0	2	33	0.0126803	0	2	2	1
34	−0.0003288	1	6	0	2	34	−0.0031828	2	3	2	1
35	0.0001165	2	6	0	2	35	0.0033427	0	6	2	1
36	0.0006909	0	0	1	2	36	−0.0018349	1	1	0	2
37	0.0042175	0	3	1	2	37	0.0001125	3	2	0	2
38	5.652E−05	3	6	1	2	38	−2.972E−05	3	6	0	2
39	−0.0014656	0	3	2	2	39	0.0002696	1	0	1	2
						40	0.0008327	2	0	1	2
						41	0.0015533	0	2	1	2
						42	0.0003027	0	6	1	2
						43	−0.0001843	0	0	2	2
						44	−0.0004254	0	3	2	2
						45	8.692E−05	3	3	2	2
						46	−0.0004659	0	6	2	2
						47	5.542E−05	1	6	2	2

Table 3. Principal characteristics of the investigated ship.

Parameter	Value
Length on water line (m)	205
Length between perpendiculars (m)	200
Beam (m)	32
Draft (m)	10
Draft at F.P (m)	10
Draft at A.P (m)	10
Trim angle (degrees)	0.00
Displacement (ton)	38430
Volume (m^3)	37500
Block coefficient	0.571
Prismatic coefficient	0.583
Midship section coefficient	0.98
Waterplane coefficient	0.75
Propeller Diameter (m)	8
Number of blades	3
P/D	0.9-1
AE/Ao	0.6

Figure 6. Computed resistance for the investigated displacement ship.

Figure 7. Simulation of acceleration of investigated ship: (a) P/D = 0.9 and (b) P/D = 1.0.

Table 4. Upper and lower bands of the propeller.

Targeted parameter	Upper band	Lower band
Propeller Diameter (m)	6	10
AE/Ao	0.3	1.1
P/D	0.6	2.0
Number of blades	3	6

Table 5. Upper and lower bands of the propeller.

	Maximum blade thickness (% of D)
r/R	Z = 3	Z = 4	Z = 5
0.2	4.06	3.66	3.26
0.3	3.59	3.24	2.89
0.4	3.12	2.82	2.52
0.5	2.65	2.40	2.15
0.6	2.18	1.98	1.78
0.7	1.71	1.56	1.41
0.8	1.24	1.14	1.04
0.9	0.77	0.72	0.67
1.0	0.30	0.30	0.30

Figure 8. Comparison of the acceleration performance of the ship with and without optimised propeller.

Figure 9. Comparison of the rotation speed of the ship with and without optimised propeller.

Table 6. Initial values and optimised values of parameters.

Targeted parameter	Initial value	Optimised value
Propeller Diameter (m)	8	8.25
AE/Ao	0.8	0.77
P/D	0.9	1.89
Number of blades	3	4

Figure 10. Comparison of the propeller efficiency of the ship with and without optimised propeller.

Figure 11. Comparison of thrust force coefficient of the ship with and without optimised propeller.

Figure 12. Comparison of torque coefficient of the ship with and without optimised propeller.

Olivieri A, Pistani F, De Mascio A. 2003. Breaking wave at the bow of a fast displacement ship model. J Mar Sci Technol. 8(2):68–75.

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Olivieri A, Pistani F, Avanzini A, Stern F, Penna R. 2001. Towing tank experiments of resistance, sinkage and trim, boundary layer, wake, and free surface flow around a naval combatant insean 2340 model, IIHR Technical Report No. 421.

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