• 作者： 黃榮鑑; 鄭仙偉
• 作者服務機構： 中央研究院物理研究所
• 中文摘要： 本文利用變向隱示法的數值解析由 Navier-Stokes 運動方程式、連續方程式及密度的擴散方程式以探討二維密度層變流通過一半圓柱形障礙體的流場變化及背面波形成的特性。研究結果顯示流體的層變將促使在障礙體背面形成的背面波(Lee waves) 有旋轉的現象發生。同時，在障礙體之前方及其下游處亦分別形成阻滯區及分離區。其形成與發展受流場的流動及密度福祿數所影響。
• 英文摘要： Numerical techniques of ADI method for integrating the time-dependent Navier-Stokes equations, which have proven useful in the study of homogeneous viscous flows, have been extended to handle theflow of a stably stratified viscous fluid over a ridge of semi-circular cylinder of infinite length. Variousproperties of the flow field and the characteristics of the lee waves formulated are investigated. Results show that the stratification tends to encourage the development of overturning flow regions(rotors) on the lee slope of the ridge and the formation of such region on the upstream slope and down-stream from the ridge. For stratified flows over obstacles, the fluid below the top of the obstacle becomespatially blocked for flows of slow motion or small values of internal Froude number.
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