scholarly journals Multi-Objective Hydrodynamic Optimization of the DTMB 5415 for Resistance and Seakeeping

2015 ◽  
Author(s):  
Matteo Diez ◽  
Andrea Serani ◽  
Emilio F. Campana ◽  
Omer Goren ◽  
Kadir Sarioz ◽  
...  
Keyword(s):  
Computational Methods ◽  
Task Group ◽  
Test Case ◽  
Multi Objective Optimization ◽  
Hull Form ◽  
Multi Objective ◽  
Average Improvement ◽  
Hull Forms ◽  
Hydrodynamic Optimization

The paper presents recent research conducted within the NATO RTO Task Group AVT-204 “Assess the Ability to Optimize Hull Forms of Sea Vehicles for Best Performance in a Sea Environment.” The objective is the improvement of the hydrodynamic performances (resistance/powering requirements, seakeeping, etc.) of naval vessels, by integration of computational methods used to generate, evaluate, and optimize hull-form variants. Several optimization approaches are brought together and compared. A multi-objective optimization of the DTMB 5415 (specifically the MARIN variant 5415M) is used as a test case and results obtained so far using low-fidelity solvers show an average improvement for resistance and seakeeping performances of nearly 10 and 9%, respectively.

Asynchronous Master-Slave Parallelization of Differential Evolution for Multi-Objective Optimization

2013 ◽  
Vol 21 (2) ◽  
pp. 261-291 ◽  
Author(s):  
Matjaž Depolli ◽  
Roman Trobec ◽  
Bogdan Filipič
Keyword(s):  
Computer Architecture ◽  
Optimization Problem ◽  
Computer Architectures ◽  
Parallel Computer ◽  
Test Case ◽  
Multi Objective Optimization ◽  
Multi Objective ◽  
Performance Results ◽  
Insight Into ◽  
Industrial Optimization

In this paper, we present AMS-DEMO, an asynchronous master-slave implementation of DEMO, an evolutionary algorithm for multi-objective optimization. AMS-DEMO was designed for solving time-intensive problems efficiently on both homogeneous and heterogeneous parallel computer architectures. The algorithm is used as a test case for the asynchronous master-slave parallelization of multi-objective optimization that has not yet been thoroughly investigated. Selection lag is identified as the key property of the parallelization method, which explains how its behavior depends on the type of computer architecture and the number of processors. It is arrived at analytically and from the empirical results. AMS-DEMO is tested on a benchmark problem and a time-intensive industrial optimization problem, on homogeneous and heterogeneous parallel setups, providing performance results for the algorithm and an insight into the parallelization method. A comparison is also performed between AMS-DEMO and generational master-slave DEMO to demonstrate how the asynchronous parallelization method enhances the algorithm and what benefits it brings compared to the synchronous method.

Multi-objective optimization of the hull form for the semi-submersible medical platform

2021 ◽  
Vol 230 ◽  
pp. 109038
Author(s):  
Xiaojie Tian ◽  
Xiaoyuan Sun ◽  
Guijie Liu ◽  
Yingchun Xie ◽  
Yu Chen ◽  
...  
Keyword(s):  
Multi Objective Optimization ◽  
Hull Form ◽  
Multi Objective

Hull Form Optimization of Performance Characteristics of Turkish Gulets for Charter

2005 ◽  
Author(s):  
Mark Gammon ◽  
Abdi Kukner ◽  
Ahmet Alkan
Keyword(s):  
Stability Index ◽  
Hull Form ◽  
Multi Objective ◽  
Cost Of Resistance ◽  
Optimization Methodology ◽  
Hull Forms ◽  
The Stability ◽  
Traditional Construction ◽  
The Cost ◽  
Survival Of The Fittest

Turkish Gulets are motor-sailors that are still being built using wooden boatbuilding traditional construction in the Aegean and Mediterranean as well as being built using steel and cold moulded techniques. They are typical of the craft used for skippered charter tours in the region and exhibit good seakeeping in the shorter steep sea of the Mediterranean and also for manoeuvring in port and in anchorages. Usually this performance is at the cost of resistance. Sailing performance and stability are surprisingly not considered due to the large beams. The hull forms of two typical gulets are used to examine the stability, resistance and coupled heave and pitch. A multi-objective evolutionary optimization methodology is used to investigate the performance of the three objectives. The evaluation of resistance uses a transom modified Michell theory in keeping with the smaller L/B ratios and large transoms of many of these vessel types. Seakeeping is evaluated using a strip motion program and the stability curve is used to provide a stability index. The multi-objective analysis is based on the optimization capabilities of genetic algorithms. Evolutionary algorithms are stochastic in nature and follow the Darwinian principle of survival of the fittest. From a given population of hull candidates, those hulls that are “fitter” by having better resistance, seakeeping and stability are selected to generate a new population. Over the course of many generations, the hulls are optimized to provide better performance. Each of the objectives requires an index to measure the performance of the candidate.

Hull Form Optimization of a TriSWACH for Reduced Drag

2015 ◽  
Author(s):  
Fuxin Huang ◽  
Lijue Wang ◽  
Chi Yang ◽  
Richard A. Royce
Keyword(s):  
Drag Reduction ◽  
Surrogate Model ◽  
Objective Functions ◽  
Hull Form ◽  
Multi Objective ◽  
Speed Range ◽  
Hydrodynamic Optimization

A new methodology for hydrodynamic optimization of a TriSWACH is developed, which considers the shape of the center hull only and its optimal results are not influenced by the position configuration of side hulls. In order to accelerate the process of the optimization, a practical multi-objective hydrodynamic tool has been further developed by integrating a surrogate model to approximate the objective functions and constraints. The proposed method and the further developed tool are applied to optimize the hull form of a TriSWACH with nine possible side hull position configurations for reduced drag. A considerable drag reduction is obtained by the optimal TriSWACH for various side hull configurations and speed range.

Hull Form Optimization Based on an NM+CFD Integrated Method for KCS

2020 ◽  
Vol 17 (10) ◽  
pp. 2050008
Author(s):  
Aiqin Miao ◽  
Decheng Wan
Keyword(s):  
Optimization Design ◽  
Model Building ◽  
Computational Cost ◽  
Hull Form ◽  
Integrated Method ◽  
Computational Fluid Dynamics Cfd ◽  
Hull Forms ◽  
Main Components ◽  
Hydrodynamic Optimization ◽  
High Computational Cost

This paper concerns development and illustration of a hydrodynamic optimization tool, OPTShip-SJTU, which contains four main components, i.e., hull form modifier, performance evaluator, surrogate model building, and optimizer module. It has been further developed by integrating a new method into the performance evaluator module, which combines the Neumann–Michell (NM) theory with computational fluid dynamics (CFD) technology, in order to reduce the high computational cost. To illustrate the practicality of further extension, OPTShip-SJTU was applied to optimize the hull form of KCS by simultaneously reducing drags at two speeds. A drag reduction was obtained by the optimal KCS of different hull forms. It turns out the presented method for ship optimization design is effective and reliable.

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