## 會議論文

 學年 98 1 2010-11-16 魚類群游之流體動力學數值模擬研究 Numerical Investigation on Swimming Hydrodynamics of Fish School 湯敬民; 李蓮吟 淡江大學航空太空工程學系 臺北縣淡水鎮 : 淡江大學航空太空工程學系 第七屆海峽兩岸航空太空學術研討會 臺北縣, 臺灣 本文以數值模擬之方式研究魚群呈三角形排列方式群體游動時的省能機制，當二維流場之Re=5000 ，經求解二維不可壓縮黏滯性的Navier-Stokes 方程式進行數值模擬，本文設定可產生最佳游動效率 之史卓荷數為0. 3 ，調整下游魚隻之距離(s =1.25、1. 35 、1. 5 、1. 65 、1.75 、2 ) ， 探究下游魚隻 最佳之省能位置與機制。本文歸納出之最佳下游位置為s= 1. 5L，下游魚隻受上游剝離之低壓尾流同向 吸力之影響，可較單獨游動時減少45%功率之消耗; s=1.25 L 則是減少消耗最少功率之下游位置，下 游魚隻僅較單獨游動時減少9% 的功率消耗。若下游魚隻之位置超過s= 1. 5 L( 即超過1. 5 倍身長) ，則 因低壓尾流受流體黏滯性影響，較消散甚至減弱，下游魚隻受到上游剝離之低壓尾流的影響較少，因 此能減少消耗之功率並不多。 The objective of this research is to study the energy saving· mechanism of group-swimming fish via numerical simulation. Two-dimensional Navior-Stokes equations have been solved in a viscous, incompressible flow with Re = 5000. For better swimming performance, the Strouhal number was set at 0.3. Simulations with various spacing (s = 1.25L ' 1.35L ' 1.5L ~ 1.65L ' 1.75L ' 2L, where L is the length of the fish) between the fish in stream-wise direction have been carried out to find the optimum value. Results showed that, due to the suction effect induced by low pressure wake region caused by tail sweeping of the fish at the upstream side, power consumption of the fish with s = 1.5L downstream-wise was 45% less than that when swimming alone. However, with spacing s = 1.25L, the power consumption of the downstream side of the fish was only 9% less than that when swimming alone. Since the low pressure suction effect was dissipated gradually by viscosity, the influence from the upstream side of the fish upon the downstream side of the fish became smaller when the spacing was greater than 1.5L. Thus, the benefit of energy saving in group swimming became less distinct. 魚群;數值模擬;低壓尾流;省能;fish school;numerical simulation;Low-pressure wake;power consumption zh_TW 兩岸 淡水校園 20101116~20101116 TWN Y 第七屆海峽兩岸航空太空學術研討會論文集，頁209-218 機構典藏連結 ( http://tkuir.lib.tku.edu.tw:8080/dspace/handle/987654321/84793 ) 機構典藏連結