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題 名 | Numerical Predictions of Unsteady Transonic Aerodynamics with Truncation Error Injection=截尾誤差注入法應用於非穩態穿音速氣動力數值計算之研究 |
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作 者 | 傅健康; 游義地; | 書刊名 | 筧橋學報 |
卷 期 | 5 1998.09[民87.09] |
頁 次 | 頁23-42 |
分類號 | 447.553 |
關鍵詞 | 非穩態穿音速流; 截尾誤差注入法; 顫震界限; Unsteady transonic flow; Truncation error injection; Flutter boundary; |
語 文 | 英文(English) |
中文摘要 | 本文旨在利用一種截尾誤差注入法(Truncation Error Injection Method)來進 行非黏性,低頻率,非穩態穿音速流氣動力之數值計算。此項數值技巧的基本理念在於利用 由細格點上之穩態解,經內插後並求得截尾誤差,以便注入粗格點上來求得非穩態解。如此 將不但可藉由正確估算之截尾誤差,在不同的(粗)格點上求得較準確的解,而且可選用分 別與穩態及非穩態相當之特徵長度的不同格點,來做最有效之計算。本文中分別計算傳統之 NACA 64A010 及超臨界 NLR 7301 兩種翼剖面上之穩態及非穩態穿音速氣流。由計算結果發 現利用截尾誤差注入法,可在粗格點上求得較為準確之細格解,但此舉卻可節省大量的(超 過 90 %)計算時間及記憶容量,此數值技巧可以只需經由少許的修改而被有效地應用在各 個現行的計算程式中,尤其是在推廣至三維非黏性及黏性之非穩態穿音速流空氣動力之計算 上,頗具實用參考價值。 |
英文摘要 | A numerical technique, called truncation error injection, is introduced for efficient computations of inviscid, low-frequency unsteady transonic aerodynamics. This technique is based on the ideas of approximating the truncation error on a base grid using steady state solutions on finer grids, The steady flow corresponding to body shape is maintatined by truncation error injection while the perturbed unsteady flows corresponding to unsteady body motions are being computed. It can be shown that with accurate prediction of the truncation error, it is possible to obtain any solution on different grids, including the exact one to the differential equation that the difference equation is representing. This allows the use of different grids comparable to the characteristic length scales of steady and unsteady flows and, hence, allows efficient computation of the unsteady perturbations. Examples of typical unsteady computation of flows over a conventional airfoil-NACA 64A010 and a supercritical airfoil-NLR 7301. These computed results show that a fine grid solution can be obtained on a coarse grid by truncation error inclusion, and substantial savings in computation time (more than 90%) and storage without loss of solution accuracy can easily be achieved using this method. This technique can also be easily applied to any existing computer code with only a few modifications. An extension of application of this method for the computations of the three-dimensional, inviscid or viscous, unsteady transonic aerodynamics is straightforward. |
本系統中英文摘要資訊取自各篇刊載內容。