The research on hull form performance and application of China offshore maintenance vessel for wind farm

Introduction

In this paper, a preliminary study is carried out on the ship form scheme of monomer、catamaran and trimaran and their performance, in order to provide some reference for the selection and application of operation and maintenance ship for wind farm.

Approach

CFD numerical simulation method

Main body of abstract

1 Monomer hull form scheme
In the high-speed monohull ship usually includes round bilge type and knuckle type. Round bilge craft has better performance of resistance, but the seakeeping performance is not good in waves, especially roll characteristics. The seakeeping performance of knuckle type ship is greatly improved than round bilge hull, but the resistance is relatively poor in still water.
Round & knuckle craft has both round bilge hull excellent resistance performance, and the good rolling performance of knuckle type. In order to further explore the round & knuckle ship type resistance performance, This paper designed and constructed a high speed operation and maintenance mono-hull ship, based on the analysis of relative length of operation and maintenance mono-hull ship for wind farm with different angle lines(the ratio of angular line length and the total length ). Its total length is 23.8m, total width is 5.3m, moulded depth is 2.7m, draft is 1.2m, the installed power is 2×368kw, the speed is 20kn.
2 Catamaran ship scheme
Based on the conventional catamaran, this paper take the advantages of the small waterline aera twin hull ship, and adopt the relative length of the larger bulbous head and stern ship to obtain excellent resistance and seakeeping performance.
Therefore, this thesis aims at the operation and maintenance catamaran for wind farm, the ship form of the catamaran with big bulbous head and stern resistance performance is significantly higher than that of conventional catamaran by using CFD numerical simulation method. But in consideration of reducing the construction difficulty and so on, wind farm in China is building a small conventional catamaran operation and maintenance of the ship and its total length is 20.6m, total width is 7.0m, type deep is 2.7m, draft is 1.35m, the installed power is 2×298kw and full load speed is 18kn.
With the increasing scale of operation and maintenance catamaran for wind farm, big bulbous head and stern ship scheme will be applied in practical application，in order to further improve its fast performance and to reduce the pitch and heaving amplitude.
3 Trimaran ship scheme
Compared with mono hull ship with the same length, trimaran has larger deck area, better seakeeping performance and better propulsive performance. Compared with catamaran, trimaran can avoid catamaran ship twisting and anxious shake, and can reduce the pitch and heave.
For trimaran, the proportion of the displacement of the side body and the relative position of the main body has an important influence on its performance. Therefore, for a operation and maintenance catamaran for wind farm, under the condition of same main scale and same draft with, this paper set the ratio of side hull displacement to total displacement was 9%, 12%, 15% and 18% respectively, to explore the scheme of low resistance, and on this basis, the design variables are the vertical and horizontal position of the side-hull, to minimize total resistance value and the value of pitch and heave motion in irregular waves as the optimization objective, by setting weight method to determine the objective function, to apply a multi objective optimization of the side layout of trimaran maintenance ship.

Conclusion

In view of Chinese offshore wind farm has begun to take shape and have been put into operation in succession, the demand for maintenance ships is also becoming more and more urgent. Several types of ship types explored in this paper can provide some help for the selection of maintenance ship.



Learning objectives
Several types of ship types explored in this paper can provide some help for the selection of maintenance ship.