【摘要】 本文通过实验研究二维单圆柱尾迹中心对称面和剪切面上流向速度脉动的自谱、互谱的空间演化特征,发现:(1)脱落主导频率及其一阶亚谐波间可发生波数匹配,且空间相位演化呈直线型的主导频率在以其为中心的一定频带中可发生波数匹配,发生波速匹配的频率并非需要具有可比的能量,圆柱中心面相对剪切面更易发生波数匹配;(2)脱落主导频率及其一阶亚谐波、谐波具有较为确定的空间相位关联。更多还原

【Abstract】 This experimental study was put emphasis on the spatial evolutions of self- and cross-spectra of the streamwise velocity fluctuations on the middle-symmetric-plane and shear-layer-plane of two-dimensional wakes of a circular cylinder.It finds experimentally that(1) the representative shedding-frequency with its first sub-harmonic wave leads to wave-number-matching,the frequencies those happening to wave-number-matching do not need to have the comparable energy,the middle-symmetric-plane is more easy to set up wave-number-matching than the shear-layer-plane;(2) the representative shedding-fre-quency with its first sub-harmonic and harmonics waves have the determinable spatial-phases.更多还原