| Summary: | 碩士 === 國防大學中正理工學院 === 造船工程研究所 === 94 === The technique of micro-bubble drag reduction can reduce the skin friction resistance of surface ship and that of submerged body. Consequently, raising the performance of marine vehicles and lowering the consumption of energy sources will be reached. In the past study of the experiment on micro-bubble drag reduction, we found that the efficiency of drag reduction would decrease as the average void ratio (CV) exceeded some critical value. The lower the flow velocity is, the earlier this phenomenon was produced, which maybe destroy the form of turbulent boundary layer. Hence, the factors of the microbubbles greatly influence the efficiency of drag-reduction technology. At the present, the results of research show the most important control factors for drag-reduction technology include the formation of microbubbles, the microbubbles size, the microbubbles concentration distribution, the injection angle, the distance of injection position, and the flow speed. The main objective of this study is to find out the optimum parameter level for the technique of microbubbles drag reduction by using "Design of Experiments (DOE)" method.
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