|題名: ||Aerodynamics of a Vibrating Square Prism in Homogeneous Turbulent Flows|
|作者: ||Lu, Po-chien;Chen, Rou-hwa;Cheng, Chi-ming;Huang, Jean-houng|
|關鍵詞: ||Forced oscillating;Lock-in;Homogeneous turbulent flows;強制振動;鎖定現象;均勻紊流場|
|上傳時間: ||2013-07-11 12:00:35 (UTC+8)|
|出版者: ||Taipei : Chinese Institute of Chemical Engineers|
|摘要: ||A series of experiments have been conducted to investigate the mean drag coefficient (CD ), fluctuating drag coefficient (CD‘), fluctuating lift coefficient (CL‘), spanwise correlation, vorticity of the wake, wake velocity spectrum and lift spectrum of a square prism due to forced vibration normal to approaching turbulence flows. The frequencies and amplitudes of vibration, the turbulence intensities, and the length scales of flow fields have been controlled as the parameters of the experiments.
The results show that the wind coefficients are much greater when the oscillating cylinder is in the lock‐in range rather than stationary and reach peak value at the resonant frequency, while the wake vorticity attains maximum values.
High turbulence intensity will weaken the vortex shedding due to the effect of shear layer mixing, so the wake vorticity and wind coefficients, CD and CL’, respectively, and the peak values of the spectrum of velocity and lift force will be decreased, while, on the contrary, CD’ will increase. As the turbulence length scale increases, the vorticity of wake and wind coefficients will increase proportional to the oscillating amplitude.
|關聯: ||Journal of the Chinese Institute of Engineers=中國工程學刊 19(3), pp.353-361|