Vinsamlegast notið þetta auðkenni þegar þið vitnið til verksins eða tengið í það: http://hdl.handle.net/1946/23800
Trawl-doors are one of the main contributor of resistant produced by trawlers fishing gear, that has considerable effects on fuel consumption. A key factor in reducing that consumption is by implement computational models in the design process. This study presents a robust two dimensional computational fluid dynamics models, that are able to capture the non-linear flow past multi-element hydrofoils. Efficient optimization algorithms are applied to the design of trawl-doors, using problem formulation that captures true characteristics of the design space where lift-to-drag ratio is maximized. Four to seven design variables are used in the optimization process depending on the model, they control angle of attack, position and orientation of a slat or slat and flap. The optimization process involves both multi-point space mapping, and mixed modelling techniques that utilizes space mapping to create a physics-based surrogate model. The results demonstrate that lift-to-drag maximization is more appropriate than lift-constraint drag minimization and that local search using multi-point space mapping can yield satisfactory design at low computational cost. By using Global search with mixed modelling a solution with higher quality will be obtained, but it is not as computationally efficient as multi-point space mappin
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IMJ Theisis final.pdf | 6.17 MB | Opinn | Heildartexti | Skoða/Opna |