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題 名 | 螺類在流體逆境之行為與型態=Behaviors and Morphology Responses of Freshwater Snails to Hydraulic Stress |
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作 者 | 林秉石; 張文亮; | 書刊名 | 農業工程學報 |
卷 期 | 49:4 2003.12[民92.12] |
頁 次 | 頁12-24 |
分類號 | 361.522 |
關鍵詞 | 淡水螺類; 物流體力學; 生態工程; Freshwater snails; Bio-fluid mechanics; Ecological engineering; |
語 文 | 中文(Chinese) |
中文摘要 | 生態工法必須以生物的觀點來設計,特別對於位居食物鏈低層且對環境敏感性高的淡水螺類。本研究是以生物流體力學觀點,探討淡水螺類對於不同流速下所產生生物機械之反應,以及其適應的能力,以提供生態工程設計之參考。研究物種為石田螺、川螲、瘤蜷等三種常見的淡水螺類,研究中發現,三種螺類分別在形狀上以及行為上(腹足吸附力、攻角改變)對適應流體動力的差異性。實驗求得三種螺類在不同流速下的升力係數與阻力係數,在Re為500時,石田螺、川蜷、瘤蜷的阻力係數值分別為15.97、14.76、10.56;升力係數值分別為19.26、17.57、18.23,Re為5000時阻力係數分別為1.79、1.30、0.91;升力係數分別為0.91、0.46、0.39。螺殼的長寬比、偏心距與螺高比越低,殼口直徑與螺高比越高,表示螺殼型態越呈流線型,升力係數與阻力係數值也越低。 由水槽實驗中發現,瘤蜷76cm/sec,石田螺105cm/sec,川蜷165 cm/sec為50%螺類不被沖走之流速上限。工程設計上也需要維持斷面多樣性以及不同流速提供不同物種棲息。 |
英文摘要 | Ecological engineering should be designed with the living organisms in mind, epically the freshwater snails which are at the bottom layer of the food chains, and they are highly sensitive to the environment. This paper discusses the response and the adapt ability of the freshwater snails in different water velocities in view of bio-fluid mechanics to provide information for ecological engineering design. This study focuses on three species of freshwater snails, which are not rare in Taiwan (Sinotaia quadratus, Semisulcospira libertine, Tarebia granifera), According to our data, each species is different with regard to its shell shape and behaviors for adapting fluid dynamics. Consequently, we can explain why different species have different distributions with various water velocities. The lift coefficient and drag coefficient of the snails in different water velocities can be obtained by experiments. As Reynolds number is 500, the respective drag coefficient of three species is 15.97, 14.76, 10.56; and the respective life coefficient is 19.26, 17.57, and 18.23. When Reynolds number is 5000, the respective drag coefficient of three species is 1.79, 1.30, 0.91; and the respective life coefficient is 0.91, 0.46, and 0.39. Therefore, the lower the ratio of shell length to shell width and the ratio of shell eccentric distance to shell height, or the higher the ratio of the diameter of shell cavity to shell height, which means the shell shape is nearly streamlining, the life coefficient and drag coefficient will be lower. By the flume experiment, we found that the maximum velocity for the dislodge ratio lower than 50% is 76cm/sec, 105 cm/sec, 165 cm/sec, for Tarebia granifera, Sinotaia quadratus, Semisulcospira libertine respectively. Various water velocities and channel sections should be maintained in engineering design, to provide multiple habitats for different aquatic species. |
本系統中英文摘要資訊取自各篇刊載內容。