Development and Parallel Application of a Fast Core-Spreading Vortex Method
碩士 === 國立臺灣大學 === 機械工程學研究所 === 96 === In this study, a fast vortex method is successfully developed based on a resurrected core-spreading vortex method and on a multipole method. In this fast vortex method, the flow domain is first divided into cells of various levels via an adaptive-domain-decompos...
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| Format: | Others |
| Language: | zh-TW |
| Published: |
2008
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| Online Access: | http://ndltd.ncl.edu.tw/handle/87449116959135334130 |
| Summary: | 碩士 === 國立臺灣大學 === 機械工程學研究所 === 96 === In this study, a fast vortex method is successfully developed based on a resurrected core-spreading vortex method and on a multipole method. In this fast vortex method, the flow domain is first divided into cells of various levels via an adaptive-domain-decomposition technique. The mutually-induced velocities among vortex blobs are calculated either directly by the Biot-Savart law (point-to-point formula) or by a truncated Laurent series (box-to-point formula). The judgment is made according to the cell-to-cell relation with the help of a binary numbering system of cells, which is designed to quickly figure out the neighbors of a cell and of its mother. A fast summation algorithm is also developed to sum over all mutually-induced velocities efficiently. If we rearrange the truncated Laurent series properly, the efficiency can be increased. The accuracy and the efficiency of this fast algorithm are then examined thoroughly. The influences of relevant parameters are explored and optimum values are proposed. The CPU times spent in each substep of the vortex method in a simulation of vortex merger are finally measured and analyzed.
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