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題 名 | Application of a State-space Wake Model to Rotor Aeroelasticity in Hover=不穩定旋翼尾流場理論在氣彈力學方面之應用 |
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作 者 | 蘇艾; | 書刊名 | 力學 |
卷 期 | 10:1 1994.03[民83.03] |
頁 次 | 頁1-10 |
分類號 | 440.137 |
關鍵詞 | 旋翼尾流場模式; 誘導速度; 氣彈力學; 懸空; Rotor wake model; Induced flow; Aeroelasticity; Hover; |
語 文 | 英文(English) |
中文摘要 | 一個新的三度空間不穩定旋翼尾流場理論(以誘導速度來表示)已被推導出來。 它可以適用於直昇機旋翼在垂直飛行(包含懸空)及前飛狀態。與其它先進模式不同的是此 誘導速度在旋翼面方位角方向以傅力葉級數來表示,而在徑向以賴勤德函數來表示。每一個 級數項之係數是由一組一階常微分聯立方程式來決定,而且可表示在時間或頻率之領域中。 力函數是由使用者自己所提供的葉片負載之積分量來決定。 因為諧和數及徑向函數之取法是很有彈性的,所以使用者可以針對要解決特定的氣彈力學問 題來調整其多寡。現在我們將此尾流場模式與彈性葉片拍動方程式結合在一起來決定空氣動 力流場對結構振幅之影響。結果顯示此尾流模式具有快速收斂性。最重要的是證明了不穩定 誘導速度是一個很重要的物理現象而且經由尾流場頻率與彈性葉片結構頻率共振可以影響直 昇機動力學中葉片振動及穩定性。 |
英文摘要 | A new theory of 3-D unsteady aerodynamics (in terms of induced flow) with state variable formulation is offered in this study for a lifting rotor in axial (including hover) and forward flight. The induced flow is expressed azimuthally by a Fourier series and radially by Legendre functions. The magnitude of each term is determined from first-order differential equations in either the time of frequency domain. The forcing functions are user-supplied, radial integrals of the blade loadings. The user has the option of truncating the expansion to fit the particular aeroelastic problem of interest in light of the fact that the choice of number of harmonics and radial functions for each harmonic is flexible. In this study, this model is coupled with elastic-blade flap equations in hover in order to determine its effect on aerodynamic damping. The results show that the present model converges with three shape functions per harmonic. More importantly, results indicate that the aerodynamic damping of flexural oscillations can become small when "resonances" are encountered. Consequently, blade vibrations and stability could be seriously affected. |
本系統中英文摘要資訊取自各篇刊載內容。