The Effects of Wake Dynamics and Trailing Edge Flap on Wind Turbine Blade

[[abstract]]In the present study, we considered the bladewake interaction (BWI) and the TEF span length, index angle on a turbine blade. The aerodynamic loads and the stresses on the blade were studied. The wake dynamic theory, BEM, and the ANSYS-FORTRAN APDL method were employed. Results were correlation with a small turbine for blade stress distribution. The blade lift distribution was also compared with numerical results from [6]. Finally, the wake and the TEF configuration effects on a 5MW turbine blade in the lift distribution and stresses were presented in this work.[[cooperationtype]]國內[[conferencetype]]國際[[conferencetkucampus]]淡水校園[[conferencedate]]20140623~20140628[[booktype]]電子版[[iscallforpapers]]Y[[conferencelocation]]New Taipei City, Taiwa

[[alternative]]A Study of Beam Vibration with Nonlinear Boundaries

[[abstract]]本文將研究彈性樑在兩端點為非線性支撐的條件下，承受簡諧外力時的頻率響應分析。其中，彈性樑假設為Bemoullis-Euler beam '兩端以三次方彈簧的支撐以模擬非線性邊界條件，再利用傅立葉展開式(Fourier expansion)描述樑的運動行為。如此，以建立吾人之偽非線性振動模型。在運動方程建立完成後，利用貝索函數(Bessel function) 來模擬解析函數的形式，其次再以漢克轉換(Hankel transform) 來求其特解。觀察研究結果可發現，在非線性頻率響應分析當中會有跳躍現象Uump phenomenon)產生，其現象不只在單一頻率時發生，而是在一頻率域之中發生。由此現象可得知物體振動時的共振頻率及不穩定頻率域，而線性邊界條件假設則無法捕捉比現象。因為線性邊界條件狀況下只能觀察到物體的共振頻率。此一模型及本文所提之新的分析方式可運用在廣泛的工程問題當中，如吊橋、高速鐵路以及各種機械裝置。根據研究結果，在探討振動問題時，除了要關心共振頻率外，在非線性運動狀況下，不穩定頻率域的觀察也是極其重要的。[[abstract]]In this research, the beam vibration with nonlinear boundary conditions sustaining simple harmonic loads is studied. The elastic beam is modeled by the Bemoullis-Euler beam theory. The two ends are supported by cubic springs allowing nonlinear boundaries. The Fourier expansion is applied to the linear motion of the beam alone. However, cubic spring forces give the nonlinear constrains on the boundaries. This quasi-nonlinear analytic model for the beam vibration equation is established. The Bessel function is used to formulate the beam vibration. The Hankel transform is applied to obtain the solution. The results discover the nonlinear jump phenomenon in several frequency ranges. This gives additional information of the unstable behavior for the beam vibration, which cannot be predicted from linear approximations. This model and the new analytic technique can be applied in a wide range of engineering problems, such as suspension bridge, high speed rail road, and other mechanical devices.[[sponsorship]]中華民國航空太空學會; 國科會工程科技推展中心[[notice]]20130320格式已修正by陸桂英[[conferencetype]]國內[[conferencetkucampus]]淡水校園[[conferencedate]]20081206~20081206[[booktype]]紙本[[iscallforpapers]]Y[[conferencelocation]]臺北市, 臺

[[alternative]]The Analysis of The Point Mass Vibration Absorber on a Nonlinear Aeroelastic System

[[abstract]]本研究餘採取非線性的物理模式來模擬整個振動體之運動，非線性的物理模式停將彈簧模擬成三次方才的變化量(cubic spring) ，以使振動變成非線性的模式。並使用Multiple Scales Analysis 求得時間域性動態解析解。上述非線性系統之解析解，將與頻率域的數值解作比對，以驗證本論文之結果。本研究豆中之二維振動系統可視為翼剖面(airfoil) ，亦可視為吊橋;而單一質點減振器可視為一般之派龍架局亦可視為吊橋下之減振裝置。吾人在考慮不變動大部分的設計之下，改變減振器位置以及材料特性，達到最經濟的減振效果。[[abstract]]The Newton's second law is used to analyze a system of nonlinearly vibrational rigid body, doing pitching and plunging in conjunction with an unsteady nonlinear aerodynamic force and an absorber. The cubic spring is employed to simulate a nonlinear vibration system. The""Multiple Scales Analysis""is used to get the analytic solution in time domain. The analytic solutions will be correlated with the numerical results to ensure the nonlinear model and the effects of the absorber. By using the mathematical model presented in this study, one can adjust the position or design of the absorber to reduce vibration, without changing the main configuration or original design. In conclusion, this model has an enormous applicable value towards applied engineering and related fields.[[sponsorship]]中華民國航空太空學會; 國科會工程科技推展中心[[notice]]20130320格式已修正by陸桂英[[conferencetype]]國內[[conferencetkucampus]]淡水校園[[conferencedate]]20081206~20081206[[booktype]]紙本[[iscallforpapers]]Y[[conferencelocation]]臺北市, 臺

[[alternative]]Vibration Analysis of The Elastic Beam with a Vibration Absorber

[[abstract]]本研究係針對一橫向振動(transverse vibration) 之彈性樑'其端點以一線性彈簧支撐，另一端點分別為加入減振裝置、點質量及完全懸空在受一外力下之減振分析。吾人將比較以上三種彈性樑在不同邊界條件下的振動情況與減振效果。利用本文所推導之模式，對於結構物受到外力並開始振動之前，嘗試不同的減振裝置將可有效的避開率統共振範園，以達到系統順利運作的目的。[[abstract]]The vibration problem is very important for most mechanical devices. It is well known that the resonant phenomenon will cause serious system damage due to large displacements. Therefore a dependable and easy identified model is necessary for the prepensely design for the vibration system. In this research, we assume an elastic beam is subjected to the transverse vibration. This beam is supported with a linear spring at one of the end. The other end is attached by a point mass, an absorber and free end, and all with an external force, respectively. The analytic solutions are obtained for these 3 cases. The mode shapes and frequency responses are all studied. The effects of different vibration reduction devices on the elastic beam are analyzed. The results give important information for vibration analysis. By using derived analytic functions, one can avoid the resonance of the system efficiently by using different vibration devices.[[sponsorship]]中華民國航空太空學會; 國科會工程科技推展中心[[conferencetype]]國內[[conferencetkucampus]]淡水校園[[conferencedate]]20081206~20081206[[booktype]]紙本[[iscallforpapers]]Y[[conferencelocation]]臺北市, 臺

[[alternative]]A Study of Aerodynamic Loads on Helicopter Rotors Due to Various Blade Chord Length in Hover and Forward Flight

[[abstract]]就直昇機的研發及設計而言，首重其旋其葉片的設計，由於葉片提供了整架直昇機作各種動作時所需的升力及推力，因此葉片的外型將會直接影響到升力的大小。本研究即以Peters 的動力尾，流理論為基礎，加上葉片結轉動力學兩者合併的結合系統發展一套數學模式，將以計算出非秘態尾流場中4日:對於不同弦長葉片直昇機旋翼上的空氣動力特性。此外，對於兩種截然不同的飛行狀態:滯空和前飛亦將會在此研究中討拾。有鎧於以往葉片的設計甚少考慮尾流振動的影響，因此本研究的方法則結合了旋真的空氣動力(升力)及尾流動力結合系統並將不同葉片外形對升力的影響回饋到非種態空氣動力系統而能更精裕的預估空氣動力特性，也進一步提出更精確的葉片設計值供工業界參考。此外， 對學術界而言也提供了一套登合尾，流動力學、空氣動力學及不同葉片弦長因素之影響的方法，相信對於國內日後這方面的整合研究有抱磚引玉的賞獻。[[sponsorship]]中國航空太空學會; 淡江大學; 中山科學研究院航空工業發展中心[[conferencetype]]國際[[conferencetkucampus]]淡水校園[[conferencedate]]19951217~19951217[[booktype]]紙本[[iscallforpapers]]Y[[conferencelocation]]臺北縣, 臺

[[alternative]]The Lead-Lag Damping Analysis of a Nonlinear Rotor-Wake Coupled System

[[abstract]]本論文利用解析的方法將尾流運動方程、葉片空氣動力學及一個非線性的複材葉片的Flap-lag-torsion結構運動方程整合成一耦合的系統。該系統為一極複雜之非線性積分---偏微分方程式，本論文將利用Galerkin及Duncan多項式將其展開，求得平衡項(Equilibrium term)係數，再與擾動項(Disturbant term)合併且線性化之後，利用Floquet理論求解該系統之Flap-lag-torsion阻尼值。由結果得知，本文之Lead-lag阻尼值的預估在低仰角時與前人的實驗結果相比誤差較大，然而整體誤差較前人之數值分析結果為小。此外，本文所建立的數學模式包含尾流及複材葉片之因素且為時域內之方程式，對於旋翼葉片之 Flap-lag-torsion的Damping及穩定性的分析將又邁出一大步。[[abstract]]In this research, a new three-dimensional wake and nonlinear composite rotor blade flap-lag torsion coupled model is developed. The generalized dynamic wake model employed is based on an induced undetermined time dependent coefficients as aerodynamic states. The nonlinear composite beam theory governs the equations of motion of an extensional-flexure-flexure-torsional vibrations of a slewing or rotating beam. The nonlinear equilibrium states results are employed as the coefficients of the linearized disturbant equation. The Floquet Theory is used to find the system dampings. Results show that the error of lag damping for different pitch angles has been reduced from 40.7%~92.1% to 10.2%~34.2%. The present model thus proves to be successful.[[sponsorship]]中正理工學院; 中國航空太空學會; 中華民國燃燒學會[[notice]]20130320格式已修正by陸桂英[[conferencetype]]國內[[conferencedate]]19991204~19991204[[booktype]]紙本[[iscallforpapers]]Y[[conferencelocation]]桃園, 臺

[[alternative]]The effect of wake dynamics on elastic helicopter rotor blades in forward flight

[[abstract]]直昇機的旋翼葉片，當它在懸空或前飛時，誘導尾流會劇烈地影響到它的穩定性。本文的研究即是在探討有關 誘導尾流及旋翼葉片所形成的氣彈系統，它們之間的交互影響及穩定性分析。誘導尾流的理論係採用準確性及偶合 性極佳的彼得斯(Peters) 動力尾流理論。至於和彈性葉片耦合成的氣彈系統，我們使用Galerkin method，做為 求解彈性運動方程的工具，然後再使用修正過的Duncan多項式作為彈性葉片的彎曲模。本氣彈系統是建立在非旋 轉座標系統上，具有週期性的係數，所以必須以"富羅格(Floquet)理論"作為求解特徵值的工具。本研究的結果 即對誘導尾流及剛性葉片和彈性葉片的耦合氣彈系統作特徵值分析，由特徵值分析結果中可以了解誘導尾流對剛性 及彈性葉片Flap 阻尼具有相當程度的影響，而且於前飛時其影響的效應比懸空時更為劇烈。[[sponsorship]]中國航空太空學會; 淡江大學; 中山科學研究院航空工業發展中心[[conferencetype]]國內[[conferencetkucampus]]淡水校園[[conferencedate]]19951217~19951217[[iscallforpapers]]Y[[conferencelocation]]臺北縣, 臺

[[alternative]]Review of Helicopter Rotor Wake Dynamic Theories

[[abstract]]由於旋翼機的升力及推力皆由主旋翼負責,因此直昇機的主旋翼就扮演了重要的角色。本文的目的就是介紹歷年來直昇機主旋翼尾流力學的理論發展。首先就尾流空氣動力學的觀點介紹基本的尾流理論,如動量理論、葉片元素理論等。此外對於電腦上之應用,如自由流法也略加介紹。而對於預設尾流法及較近代之尾流理論--- Peters動力尾流理論及該理論的應用也將詳加介紹。 The development and background of rotary-wing wake dynamics has been briefly reviewed. Several basic wake aerodynamic models have been introduced. The free-wake analysis is also mentioned for the C.F. D. applications. The prescribed wake model has compared with other approach methods. A recently wake model---Peters dynamic wake model is also introduced as well as its applications in aeroelastic systems.[[abstract]]The development and background of rotary-wing wake dynamics has been briefly reviewed. Several basic wake aerodynamic models have been introduced. The free-wake analysis is also mentioned for the C.F. D. applications. The prescribed wake model has compared with other approach methods. A recently wake model---Peters dynamic wake model is also introduced as well as its applications in aeroelastic systems.[[sponsorship]]淡江大學 航空工程系[[conferencetype]]兩岸[[conferencetkucampus]]淡水校園[[conferencedate]]19951214~19951215[[booktype]]紙本[[iscallforpapers]]Y[[conferencelocation]]臺北縣, 臺

[[alternative]]A Flapping Mode Identification of Rotary Wing Blades and Wake Coupled System in Forward Flight

[[abstract]]特徵值的分析可以判定一個系統的穩定性,而對於氣體彈性力學特徵值的分析而言也是很重要的一部分。本文將用富羅格理論對葉片-尾流耦合系統做特徵值分析,並透過此法對四個葉片的旋翼在前飛時做拍撲運動的各組模態( modes)做辨識及探討。本文發現考慮尾流動力影響與不考慮誘導流系統之旋翼葉片特徵值做比較時,即使在很高的前飛率時,誘導流對葉片動力的影響仍然很大。 An eigenvalue study can provide stability information for a system, and it is also and important part of aeroelastic analysis. In this work, the blade-wake coupled system eigen- analysis is studied by the Floquet Theory, and the flapping modes for a four-bladed rotor are investigated and identified through their eigenvalues. The eigenvalues of the Floquet matrix can determine system characteristics. The effect of wake dynamics on rotor blade eigenvalues can be seen by comparison with no inflow case. The results show that the inflow has a profound effect on blade dynamics, even at high advance ratios.[[abstract]]An eigenvalue study can provide stability information for a system, and it is also and important part of aeroelastic analysis. In this work, the blade-wake coupled system eigen- analysis is studied by the Floquet Theory, and the flapping modes for a four-bladed rotor are investigated and identified through their eigenvalues. The eigenvalues of the Floquet matrix can determine system characteristics. The effect of wake dynamics on rotor blade eigenvalues can be seen by comparison with no inflow case. The results show that the inflow has a profound effect on blade dynamics, even at high advance ratios.[[sponsorship]]淡江大學 航空工程系[[conferencetype]]兩岸[[conferencetkucampus]]淡水校園[[conferencedate]]19951214~19951215[[booktype]]紙本[[iscallforpapers]]Y[[conferencelocation]]臺北縣, 臺