本文以數值模擬之方式研究魚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、2L)，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、1.35 L、1.5 L、1.65 L、1.75 L、2 L, 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 = 1.5 L downstream-wise was 45% less than that when swimming alone. However, with spacing s = 1.25 L, 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 1.5 L. Thus, the benefit of energy saving in group swimming became less distinct.

目錄
目錄	I
圖目錄	IV
表目錄	VII
第一章	前言	1
第二章	文獻回顧	3
2.1	魚類基本形態構造	3
2.2	被動控制	3
2.2-1	皮膚效應	3
2.2-2	節瘤效應	4
2.3	主動控制	5
2.3-1	游動模式	5
2.3-2	推進原理	6
2.3-3	進效率判定	8
2.4	研究方法	9
2.4-1	理論分析	9
2.4-2	數值計算	10
2.4-3	實驗量測	11
2.5	魚類群游機制(Fish School)	11
第三章	研究方法	19
3.1	物理模型	19
3.1-1	軌跡方程式之組成	19
3.1-2	無因次參數	20
3.2	統御方程式	22
3.3	數值方法	23
3.4	CFD-RC操作說明	26
3.5	模擬參數	26
3.6	網格架構	28
第四章	結果與討論	30
4.1	研究敘述	30
4.2	下游魚隻位置改變對功率之影響	30
4.2-1	下游魚隻位置改變之總功率變化	31
4.2-2	下游魚隻改變位置之阻力功率變化	32
4.2-3	下游魚隻位置改變之游動功率變化	33
4.3	流場之渦流強度	35
4.3-1	魚隻單獨游動之渦流場	35
4.3-2	下游魚隻在各位置之渦流場	36
4.4	群游與單隻魚之功率增益	37
第五章	結論與未來展望	40
5.1	結論	40
5.2	未來展望	41
第六章	參考文獻	43
 
圖目錄
圖 2-1 魚體結構示意圖	49
圖 2-2 座頭鯨鰭端節瘤圖(Bushnell and Moore , 1991)	49
圖 2-3 有無節瘤之攻角對應升力與阻力係數關係圖(Owen et al., 2000)	50
圖 2-4 有無節瘤下NACA 63-021流場結構圖(Paterson et al., 2003)	50
圖 2-5 魚類游動模式分類圖(Sfakiotakis et al., 1999)	51
圖 2-6 加速反作用力產生推進力機制說明圖	51
圖 2-7 魚類尾鰭擺動與渦流生成示意圖 (陳政宏, 2002)	52
圖 2-8 卡門渦流與反卡門渦流示意圖(Triantafyllou et al., 1993)	52
圖 2-9 蝌蚪波動所造成的渦流結構圖(Liu et al., 1999)	53
圖 2-10 鰻型魚類身推進的流場形貌，藍線表示流線(Carling et al., 1998)	53
圖 2-11 DPIV量測鯊魚尾鰭擺動雙環結構示意圖(郭子凡, 2007)	54
圖 2-12 DPIV量測鯡魚游動時滑動數改的流場形貌(Muller et al., 2002)	54
圖 3-1 NACA 0012外型圖	55
圖 3-2 物理模式圖	55
圖 3-3 a(x),魚體擺動之振幅包絡線	56
圖 3-4 CFD-ACE+中鬆弛係數之設定	56
圖 3-5 CFD-RC 之工具列	57
圖 3-6 魚群的三角形排列	58
圖 3-7 驗證兩隻魚d=0.3、0.4、0.6、1 L之總功率	58
圖 3-8 測試s = 0.15 L阻力與側向力係數	59
圖 4-1 所有位置魚群之總功率	59
圖 4-2 (a)至(f)下游魚隻(編號3)在各位置之編號1、2、3總功率變化	60
圖 4-3 下游魚隻(編號3)在各位置之總功率	61
圖 4-4 所有位置魚群之阻力功率	61
圖 4-5 (a)至(f)下游魚隻(編號3)在各位置之編號1、2、3阻力功率變化	62
圖 4-6 下游魚隻(編號3)在各位置之阻力功率	63
圖 4-7 阻力功率與游動功率之變化比較	63
圖 4-8 所有位置魚群之游動功率	64
圖 4-9 (a)至(f)下游魚隻(編號3)在各位置之編號1、2、3游動功率變化	65
圖 4-10 下游魚隻(編號3)在各位置之游動功率	66
圖 4-11 魚隻單獨游動隻連續渦流變化	68
圖 4-12 單獨魚隻游動之壓力速度場連續變化	70
圖 4-13 下游魚隻(編號3)在s=1.25 L 位置之渦流連續變化	72
圖 4-14 下游魚隻(編號3)在s=1.25 L 位置之壓力速度場連續變化	74
圖 4-15 下游魚隻(編號3)在s=1.35 L 位置之渦流連續變化	76
圖 4-16 下游魚隻(編號3)在s=1.35 L 位置之壓力速度場連續變化	78
圖 4-17 下游魚隻(編號3)在s=1.5 L 位置之渦流連續變化	80
圖 4-18 下游魚隻(編號3)在s=1.5 L 位置之壓力速度場連續變化	82
圖 4-19 下游魚隻(編號3)在s=1.65 L 位置之渦流連續變化	84
圖 4-20 下游魚隻(編號3)在s=1.65 L 位置之壓力速度場連續變化	86
圖 4-21 下游魚隻(編號3)在s=1.75 L 位置之渦流連續變化	88
圖 4-22 下游魚隻(編號3)在s=1.75 L 位置之壓力速度場連續變化	90
圖 4-23 下游魚隻(編號3)在s=2 L 位置之渦流連續變化	92
圖 4-24 下游魚隻(編號3)在s=2 L 位置之壓力速度場連續變化	94
圖 4-25 下游魚隻(編號3)位置與編號1、2、3平均功率變化	95
圖 4-26 下游魚隻(編號3)之位置與總功率、平均總功率變化	95

 
表目錄
表 4-1. 下游魚隻各位置之平均阻力功率	96
表 4-2. 下游魚隻各位置之平均游動功率	97
表 4-3. s=1.25 L 位置之功率與增益值	98
表 4-4. s=1.35 L位置之功率與增益值	98
表 4-5. s=1.5 L位置之功率與增益值	99
表 4-6. s=1.65 L位置之功率與增益值	99
表 4-7. s=1.75 L位置之功率與增益值	100
表 4-8. s=2 L位置之功率與增益值	100

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