路式雙髻鯊(Sphyrna Lewis)外型有別於一般水中生物，其頭部扁平而寬大會使阻力上升，但也因此會增加升力，且眼睛及鼻腔能擴大搜索範圍並更顯立體感。眾多研究發現鯊魚表面的盾鱗能降低阻力，本研究進一步以CFD(Computational Fluid Dynamics)探討雙髻鯊頭部翼狀外形及周遭流場變化。
為模擬鯊魚盾鱗減阻效果，以前人實驗成果為基準，用攝影測量方法建構雙髻鯊型潛體的3D模型，將檔案匯入Rhino 3D繪圖軟體修正後，使用ANSYS FLUENT CFD軟體計算雙髻鯊型潛體流體力學性能。先找出實驗中光滑條件下的摩擦係數(因為在實驗中的光滑條件不等於模擬的光滑條件)，得出摩擦係數應設為KS=1.9586E-5，再使用試誤法調整紊流模型中紊流黏度項(μt)中的經驗公式常數a1，找出與鯊魚盾鱗實驗結果相同的減阻值，最後得出a1應設為0.2955。
CFD的計算結果發現使用模擬盾鱗的雙髻鯊型潛體在阻力方面平均阻力值呈下降趨勢，在摩擦阻力方面趨勢更明顯，而在升力方面則影響不顯著。其次，在雙髻鯊頭部前緣凹槽與鼻腔構造具有流體導向的功能。頭部末端增厚的眼部結構能降低翼尖渦流(Tip vortex)的影響，而在胸鰭方面則因末端較為銳利使翼尖渦流影響較明顯，並且在胸鰭與身體交界處也會產生接面渦流(Junction vortex)，使入流穩定度些許下降，也可能導致升力下降。關於流體流經頭部與胸鰭後產生的流體擾動，雙髻鯊型潛體頭部以及胸鰭後面渦量變動對流場的影響極小。

The shape of Sphyrna Lewis is different from other aquatic creatures. Its flat and wide head can increase resistance and lift. It can also expand the search range of the eyes and nasal cavity. This makes things appear more three-dimensional. Many studies had founded that the placoid scale on the shark surface can reduce resistance. The purpose of this study is to explore the wing-like shape of the head of the hammerhead shark and the around flow field change by CFD(Computational Fluid Dynamics)..
In order to simulate the drag reduction effect of shark placoid scale. The previous experimental results were used as a benchmark to establish a 3D model of the Submerged Body with Hammerhead Shark Shape which was constructed by photogrammetry. After the files were imported into the Rhino 3D mapping software for correction, the Ansys FLUENT CFD software was used to calculate the hydrodynamic properties of the Submerged Body with Hammerhead Shark Shape. First the friction coefficient with the smooth conditions in the previous experiment was found to be KS=1.9586E-5(the smooth conditions in the experiment are not equal to the simulated smooth conditions). In order to find the same drag reduction value as the experiment result on the shark placoid scale, the trial-and-error method was used to adjust the emperiment formula constant ?1 in the turbulent viscosity term (μ_t) in the turbulence model. Finally, ?1 was concluded to be 0.2955.
The calculation results of CFD showed that the average resistance value of the Submerged Body with Hammerhead Shark Shape using simulated placoid scale showed a downward trend in terms of resistance. A more obvious trend in terms of frictional resistance, but a less significant impact on lift. The grooves and nasal structures at the leading edge of the head of the hammerhead shark have a fluid-directing function. The thickening of the eye structure at the end of the head can reduce the influence of the tip vortex, while in terms of the pectoral fin, the impact of the tip vortex is more obvious because the end is sharper. The junction vortex will also occur at the junction of the pectoral fin and the body, which will slightly reduce the stability of the inflow or might lead to a decrease in lift. Regarding to the fluid disturbances generated by the flow of fluid through the head and pectoral fin, the changes in the vortex of the Submerged Body with Hammerhead Shark Shape and behind the pectoral fin are weakened at X/L= 0.11, so the effect on the posterior fluid is minimal.

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