Title: Hull Form Optimization to Fulfil Minimum Propulsion Power by Using Frequency and Time Domain Potential Flow Solvers
Abstract: This paper presents hull form optimization processes which can be practically applied at hull form design stage. Traditionally hull form development is carried out in calm sea condition to reach target design speed with specified engine power. However, the design condition has been changing since the evolution of EEDI. It is required to satisfy not only the design speed in calm sea, but also minimum propulsion power in wave condition for ships complying with regulations on energy efficiency of IMO. Hull form optimization processes with single and multi-objective functions are described. The single-objective optimization seeks for optimized hull forms in waves from a hull form initially optimized in calm sea condition. The multi-objective optimization evolves hull forms by improving resistance performance in both waves and calm water. For the optimization processes, a practical approach using two potential flow solvers, Wasim and Wadam, which can handle forward speed problems, is presented. The approach consists of two stages: The first stage is to optimize and find best candidates by running Wadam inside CAESES, a parametric hull form optimization program. Added resistance at a required advance speed is computed and evaluated for several sea states specified by the simplified assessment of IMO MEPC.1/Circ.850. KVLCC2 hull form is modified and evaluated in the first optimization stage. The second stage is a verification stage using Wasim. Wasim has no limit in forward speed and is more accurate than Wadam in computing added resistance, while it requires more computational time. Based on the verification by Wasim, the wave added resistance of the optimal hull form is confirmed. The proposed approach employing the two solvers will help hull form designers save design time and investigate many more alternatives. It will also provide practical design information by showing a direction of how hull forms are varied to minimize the added resistance in waves.
Publication Year: 2020
Publication Date: 2020-10-04
Language: en
Type: book-chapter
Indexed In: ['crossref']
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Cited By Count: 1
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