接面渦漩之實驗研究

Experimental Investigation of Juncture Vortex

郭庭瑋(Ting-Wei Kuo)

指導教授 ： 丁肇隆 ； 林銘崇

國立臺灣大學/工學院/工程科學及海洋工程學研究所/碩士(2004年)

https://doi.org/10.6342/NTU.2004.00263

摘要

摘 要

本文應用已建立之粒子影像速度儀（Particle Image Velocimetry）在循環水槽中分別量測兩種不同幾何形狀之物體（圓柱體及NACA0018翼形體）與平板交接處之接面渦漩（juncture vortex）流場。於四種不同雷諾數之紊流流場中，主要的流場特性為物體上游對稱面處存在一渦流系統，此渦流系統之動力特性呈現不穩定震盪現象。探究兩物體之渦流場，在主渦心之位置分佈上，翼形體較圓柱體稍靠近物體與平板交接處，且結果顯示主渦心分佈位置僅與物體之幾何形狀有關，而與雷諾數似乎無明顯關係。而兩物體之接面渦漩最大渦度值及總環流量均隨著雷諾數增加而增大；在相同雷諾數下，翼形體之接面渦旋總環流量低於圓柱體之總環流量。

關鍵字

接面渦漩,渦漩,圓柱體,粒子影像速度儀

並列摘要

ABSTRACT

A Particle Image Velocimetry（P.I.V.）techniques was used in a circulation water tank to measure the juncture vortex which is formed near the intersection of two different models ( circular cylinder and NACA0018) on a flat plate. Four cases with different Reynolds numbers were tested. The results show a vortex system occurs at the symmetry plane of the flow field. It was found the center of main vortex is no fixed. However no obvious relation was found between the center positions and Reynolds numbers. It showed that the main vortex centers are distributed closer to models in NACA0018 cases than in cylinder cases. Therefore, it is concluded that the model geometry affects the locations of main vortex center.
Based on the measured velocity field, the vorticity and total circulations were calculated. It shows that the maximum vorticity and total circulation increase as Reynold number increases. It also found that the total circulations obtained in NACA0018 cases are smaller than in the cylinder cases.

並列關鍵字

Juncture Vortex,Vortex,NACA0018,P.I.V,Cylinder

參考文獻

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