flutter vi. 1.拍翅振翼;(旗帜)飘扬。 2.颤动,(心)急跳,(脉搏)浮动。 3.(心绪)不宁,坐立不安。 4.〔口语〕对人进行测谎。 He fluttered about the room nervously. 他心绪不宁地在房间里徘回。 vt. 1.振(翼);拍(翅)。 2.扰乱;使不安。 n. 1.振翼;飘扬。 2.不安,焦急,波动。 3.(身体部分的)病态阵跳。 4.〔英俚〕投机,小赌。 5.颤振。 6.图像跳动,脉冲干扰,放音失真。 7.对…进行测谎。 the flutter of wings 翅膀的拍动。 all in a flutter 心慌意乱。 cause [make] a great flutter 轰动一时。 fall into a flutter 心慌意乱。 in a flutter 心里卜卜跳。 put sb. in [into] a flutter = throw sb. into a flutter 使忐忑不安。 n. -er ,-ingly adv.
The characteristic of " lock - in " can be used to explain all kinds of nonlinear phenomenon of the stall flutter 这种频率锁定规律可以清楚地解释失速颤振的各种非线性现象。
Firstly , the airfoil ' s classic flutter ( at small attack angle ) , stall flutter ( near the static stall angle ) and response ( at large attack angle ) are analyzed . it is found from the numerical results that " lock - in " will occur at certain freestream velocity range near the static stall angle , where the frequency of the vortex will be equal to the natural frequency and the flutter has the characteristic of self - induced oscillation . when the attack angle is far from the static stall angle , the vortex will have its own frequency , which differs from the natural frequency , and the flutter has the characteristic of forced oscillation 首先研究了二维翼型的古典颤振(小攻角) 、失速颤振(失速攻角)和动力响应问题(大攻角) ,得到以下结论:在静态失速攻角附近的一定来流速度范围内,分离涡会发生频率锁定现象,分离流的频率与固有频率趋于相同,这时的振动呈现自激振动的特点;远离失速攻角时分离流频率则摆脱固有频率的影响,此时的振动具有强迫振动的特点。