Optimization of racing shell hull form

Ramsay, Brendan (2011). Optimization of racing shell hull form B.Sc Thesis, School of Engineering, The University of Queensland.

       
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Author Ramsay, Brendan
Thesis Title Optimization of racing shell hull form
School, Centre or Institute School of Engineering
Institution The University of Queensland
Publication date 2011
Thesis type B.Sc Thesis
Supervisor Michael Macrossan
David Mee
Total pages 38
Language eng
Subjects 09 Engineering
0913 Mechanical Engineering
Formatted abstract
The objective of this thesis Optimization of racing shell hull form was to find the characteristics of the ideal rowing boat hull. The rowing boat being considered was a schoolboys’ quadruple scull to be raced over a 1.5 km course and the measure of rowing boat effectiveness was defined to be minimum overall drag at the average velocity during a race. The analysis was done by making use of some simple approximations, potential flow theory and computation fluid dynamics. In the end however definitive results were not found.
 
The procedure devised to minimize the drag of a rowing boat was to create a series of simple hulls and determine the viscous and wave-making drag for each hull. Trends determined from different characteristics of the simplified hulls would then be used to modify an existing hull design. The drag of the modified hulls would then be compared with drag of the original hull. Three tools were identified to determine the drag acting on each hull; a flat approximation for viscous drag, a potential flow simulation for pressure drag and computational fluid dynamics (CFD).
 
The flat plate approximation gave results that agreed with conventional wisdom (drag is proportional to wetted area) but the MATLAB potential flow solver was too slow and tended to run out of memory before converging to a result. This meant that an even simpler estimate had to be made, that pressure drag is equal to frontal area multiplied by dynamic pressure. While this allowed some comparisons to be made it was not an accurate estimate and comparing the pressure and viscous drag components was not possible.
 
The CFD simulations were the biggest issue however. Problems with memory limited how fine a mesh could be used. Even adjusting the mesh so that certain regions had finer mesh could not give a small enough mesh to resolve the waterline problem without running out of memory. Because the water level could not be adequately modeled the hull models would not submerge properly in the water and gave erroneous drag estimates.
 
The final conclusion of this thesis was that by minimizing the surface area the viscous drag acting upon a racing shell could be limited. Increasing the length and having a constant cross section for most of the length were found to be the most effective ways of reducing the eavemaking drag. Further research is required to determine the exact balance between these factors to achieve the optimal racing shell hull form.
Keyword Hulls (Naval architecture) -- Design and construction

Document type: Thesis
Collection: UQ Theses (non-RHD) - UQ staff and students only
 
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Created: Fri, 05 Sep 2014, 16:06:25 EST by Ahmed Taha Siddiqui on behalf of Scholarly Communication and Digitisation Service