矩形截面收縮段內流場特性研究

Abstract

中文摘要關鍵詞：(1)收縮段 (2)風洞試驗收縮段是風洞系統的最重要 組件之一，一個設計優良的收縮段不但能提供其下游測試段極佳的試驗風 況，同時亦能確保試驗結果之準確性。Fang(1997)曾以數值模擬的方法檢 視正方形截面收縮段內之流況特性，並藉系統化的探討結果提出了一套考 慮周詳且易於遵循的收縮段設計程序與方法，然尚缺進一步之比對以為這 些結論的佐証。本研究乃藉實際風洞收縮段內之流況量測，並配合數值模 擬之結果，針對設計法則及考量作一驗證，並確認其設計方法之準確程度 ；其二則就前法未盡之處，獲取其他未能評估之相關風況特性，以增進吾 人對收縮段內風況特性之瞭解。研究中發現數值模擬以無滯性流解析收縮 段內流況其結果與實際流況非常吻合，可驗證Fang所提之設計法則與考量 具有相當之準確性。並由數值模擬與實測之結果提供吾人對收縮段內風況 特性之瞭解。

ABSTRACTKeywords: (1) Contraction (2) Wind Tunnel TestingsA contraction is one of the major components of a wind tunnel system. A well-designed contraction can lead to a good quality of flow in its downstream test section and ensure the accuracy of the test results. By analyzing the flow within a contraction on a systematic basis, Fang (1997) suggested a comprehensive design method for three-dimensional square-to- square contractions. Since the proposed procedure is essentially based on numerical results, further verifications are necessary. The goal of the study is two-folded: firstly, to verify the comprehensive design procedure with numerical and experimented method, and secondly to obtain more detailed flow characteristics, which were not taken into account in the numerical work.Result shows that the numerical predictions are in good agreement with the experimental data. Accordingly, the proposed method is confirmed to be adequate in the application of tunnel designs.