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題名 | 抑制圓柱中渦漩剝離現象之寬頻元素法模擬分析=Simulations of the Suppression of the Vortex Shedding of Circular Cylinder Separated Flow by Spectral Element Method |
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作者姓名(中文) | 周明德; 顏瑞和; 王安邦; | 書刊名 | 力學 |
卷期 | 13:4 1997.12[民86.12] |
頁次 | 頁311-320 |
分類號 | 440.12 |
關鍵詞 | 寬頻元素法; 分離流; 渦漩剝離; 抑制機構; Spectral element method; Sparated flow; Vortex shedding; Suppression mechanism; |
語文 | 中文(Chinese) |
中文摘要 | 寬頻元素法是近年來發展出來新計算方法,其具備了寬頻法的準確性及有限元素 法,對複雜幾何形狀的處理能力,是很適合用來模擬暫態物理問題的數值方法。本文應用此 法於抑制 (影響 ) 二維圓柱渦漩剝離物理現象之研究:首先對單一主圓柱具渦漩剝離之情 況作模擬,以驗證程式之正確性與結果網格的獨立性;其次,再對此流場加入一控制圓柱, 在固定位置下模擬不同雷諾數的流場,與實驗顯影照片作比較,並藉由數值結果,對流場流 線分佈、渦度分佈與速度分佈之比較,嘗試探討抑制流場渦漩剝離機構;加入控制圓柱後, 由於主圓柱及控制圓柱間所產生的正、負渦度值相互抵消, 造成在兩圓柱間產生一低渦度區 ;此低渦度區隔離了兩圓柱外圍兩側的高渦度區, 阻礙渦漩形成,而造成渦漩交互剝離效應 的激發機構被抑制。 |
英文摘要 | Spectral element method provides the accuracy of the spectral method and the flexibility for complex geometry as the finite element method. It is a useful numerical method to simulate phyical transient problems. The objective of the paper is to investigate the vortex suppression mechanism by a smaller control cylinder which is put at a proper position in the near-wake of the maincylinder. Firstly, the flow fields with and without the control cylinder are calculated. Comparison of the shedding frequency with the experimental data and validation of grid independent were made. Second, the control-cylinder is placed at a fixed position around the main-cylinder, the pictures of visualization obtained from experiments are compared with the numerical data which simulate the flow fields for different Reynolds numbers. The case of flow with the control cylinder shows that the positive vorticities produced by the main cylinder are cancelled out with the negative vorticities generated by the control cylinder. In consequence, a region of low vorticity flow that separates from the outer regions with large vorticities is developed. The region interferes with vortex formation and suppresses the formation of vortex shedding. |
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