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標題: 不同阻塊排列方式對三維雙噴射撞擊流場之影響分析
The Effect of Three - Dimensional Impinging Twin-Jet on A Rough Ground with Various Array of Blocks
作者: 陳怡舟
Chen, Yi-Cho
關鍵字: crossflow
ground effect
upwash fountain flow
circulating flow
出版社: 機械工程學系
摘要: 本文利用PHOENICS軟體來模擬三維垂直起降飛機(VTOL)在從事各種凹凸不平地表面起降時的流場分析。本文採用連續方程式和非穩態動量方程式,並配合SIMPLE-C法則與-雙方程式紊流模式,並以控制體積法建立有限差分方程式。本文分別就橫向流大小、塊狀阻物數量及排列方式、平板間距離等參數對壓力、速度及流場結構的影響逐一討論。無橫向流時,由於地面效應,兩噴嘴間會產生上沖噴泉。隨著橫向流的增強,會造成上沖噴泉向下游偏向,甚至於消失,並且流場中迴流區域不再對稱。阻塊的排法會改變上沖噴泉流的強度,迴流區大小、數目以及上平板最大壓力產生處。而平板間的距離增加時,地面效應對流場的影響變小,因此阻塊對流場的影響也較不顯著。
In this study, a computational fluid dynamics (CFD) code, PHOENICS is used to calculate the effect of twin-jet impingement on a rough ground with various array of blocks. Owing to the turbulent characteristic by the impinging flowfield, the continuity equation, unsteady momentum equation, and the-turbulence model are adopted to construct the model with control-volume integration for finite difference associated with SIMPLE-C algorithm. The effect to the parameter including, crossflow velocity, number and arrangement of block, and the distance of the plane on the velocity, pressure. For the ground effect, the upwash fountain flow is generated between the two jets for when crossflow is zero, and the upwash fountain flow will close to the downstream before it disappeared when the crossflow is increased. And the circulating flow will also become irregular. The magnitude of the upwash fountain flow, the size of circulating flow, and the great value of the pressure on the upper plate are also changed by the difference arrangement of block with no crossflow. If the distance of the plate is large, the position of block changing can not to influence the flowfield obviously. It also mean that the ground effect become smaller when the distance of plate become large.
Appears in Collections:機械工程學系所



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