查詢結果分析
來源資料
頁籤選單縮合
題 名 | 潛體附加慣性之計算與試驗=Calculations and Tests of Added Inertia of Submerged Bodies |
---|---|
作 者 | 王治平; 邱逢琛; 郭振華; | 書刊名 | 中國造船暨輪機工程學刊 |
卷 期 | 16:1 1997.02[民86.02] |
頁 次 | 頁1-7 |
分類號 | 444.1 |
關鍵詞 | 潛體; 附加質量; 附加慣性矩; 高階小板法; 平面運動試驗; Submerged bodies; Added mass; Added moment of inertia; Higher order panel metnod; Planar motion mechanism test; |
語 文 | 中文(Chinese) |
中文摘要 | 關於潛體在流體中運動時的附加質量及附加慣性矩之計算,一般在工程應用上多採用截片法或近似橢圓體法予以計算,這些方法除了都有勢流假設之外,前者忽略三維效應,後者則為形狀近似,然而這些假設與簡化對於計算結果的影響則未見有充分的探討。本文仍先循勢流假設,但採用考慮三維效應且屬形狀接合(close-fit)的高階小板法進行比較計算,然後利用本所現有之強制平面運動機構(Planar Motion Mechanism, PMM)進行試驗,量測潛體在實際流體中運動時之附加慣性等係數,以分別探討忽略三維效應、形狀近似、及勢流假設對計算結果的影響。由截片法、近似橢圓體法分別與高階小板法計算結果顯示三者皆頗相近,但近似橢圓體法比截片法更接近高階小板法的計算結果,亦即忽略三維效應顯然會比形狀近似造成較大的誤差。而由高階小板法計算結果與試驗結果之比較則顯示計算有20%-30% 之高估,與一般使用勢流理論估算和試驗比較之誤差趨勢相近,此應為忽略流體黏性效應所致,也是理論計算日後必須進一步考慮之問題。 |
英文摘要 | Strip method and approximate ellipsoid method are currently applied to estimate the added inertia of a submerged body moving in the fluid. Both of these methods neglect the effects of viscosity and base on the potential theory. Moreover, the former neglects the three dimensional effects while the latter approximates the body shape. There seem to be few quantitative discussion about the influence of such simplifications on the estimated results. In the present paper, as one of the most rigorous potential theory based methods, the higher order panel method, in which the three dimensional effects are considered with body surface close-fitted, is selected for comparison with the above-mentioned two methods. Then, tank tests with the Planar Motion Mechanism (PMM) for measuring the added mass and moment of inertia of a submerged body in the real fluid are conducted in the twoing tank of National Taiwan University. Finally, by the comparison between calculation and test results, the influence on the estimated results due to negligence of three dimensional effects, that due to body shape approximation, as well as that due to potential flow assumption are investigated. It is noted that all three calculation results are quite similar, no matter which method is applied. The results by approximate ellipsoid method are closer to those by the higher order panel method. In other words, negligence of three dimensional effects would cause more errors than what body shape approximation did. The results by applying higher order panel method overestimate 20%-30%, compared to the test results, which is comparable to those of other comparisons between potential theory calculations and tests. This trend may come from the negligence of fluid viscosity and deserves further study in the future. |
本系統中英文摘要資訊取自各篇刊載內容。