流過兩個不同直徑圓柱流場之數值研究

本文由巢狀網格來達到局部網格加密的效果。流場藉由 Navier-Stokes 方程及連續方程求解得之，解答邏輯過程採用分步法 (Fractional Step Method) 。對不穩定、具黏滯性且不可壓縮流流場，為求解複雜邊界，以巢狀網格解答流場過程中，含複雜邊界之障礙物則以 Ravoux 等人 [24] 發展的內嵌法 (Embedding Method) 處理之。本文數值方法以具二階精準度之中央插分法離散 Navier-Stokes 方程之空間項，時間項方面則利用 Adams-Bashforth 法處理對流項，以 Crank-Nicolson 法處理擴散項。本文首先以計算方型穴流 (Square lid-driven cavity flow) 測試本文數值模式於簡單邊界流場之有效性。透過與 Ghia 等人 [25] 的研究結果比對，結果十分吻合，證實本文數值模式之正確性，本文並以不同尺度網格計算結果，證實本文數值模式應用於簡單邊界流場具2階精準度。隨後，本文以 Wannier Flow 測試內嵌法於含複雜邊界流場之應用性。最後，我們應用巢狀網格法於渦漩逸出流場之抑制研究。

關鍵字

巢狀卡氏網格；數值方法；內嵌法

並列摘要

This article achieves the partial grid encryption by the nest shape grid the effect. The flow field solves it because of the Navier-Stokes equation and the equation of continuity, the explanation logical process uses the method of fractional steps (Fractional Step Method). To unstable, mounts the viscosity and the incompressible flow flow field, for the solution complex boundary, by the nest shape grid explanation flow field process, obstacle of including the complex boundary by the Ravoux et al. [24] development's in inlays the law (Embedding Method) to process it. This article numerical method by has second-order accurate the central committee to insert a minute law to be separated space of item the Navier-Stokes equation, a time aspect using the Adams-Bashforth law processing convection item, by Crank-Nicolson law processing proliferation item. This article first calculates Fang Xingxue the class (Square lid-driven cavity flow) to test this article numerical model validity in the simple boundary flow field. By with Ghia et al. [25] findings compared to right, the result tallies, confirmed that accuracy of this article numerical model, this article and by the different criterion grid computed result, confirmed this article numerical model applies in the simple boundary flow field has second-order accurate. Afterward, this article test inlays the law by Wannier in the Flow to contain utility of the complex boundary flow field. Finally, we apply the nest shape method of lattice to suppress the research in the turbulence transgression flow field.