Vortex structure model in the turbulent boundary layr interacted with longitudinal vortex arrays (1996)

本文通过实验研究了自由流动中引入的湍流边界层和纵向涡阵列之间的相互作用，以阐明这种相互作用对涡结构和边界层结构的影响。在自由流中人为地产生了展向周期性的纵向涡列。其中一个参数，纵向涡的展向周期性L/S(L表示相邻翼型之间的展向距离，S表示翼型展宽)，这两个参数都决定了在湍流边界层内产生的次生涡的大小和流向路径。间歇因子分布揭示了对向旋转二次流的影响，表现为翼型中部的下洗流动和相邻翼型中心切片的上洗流动。间歇系数受相邻翼型间距的影响很大。间歇因数的值在t…中减小在翼型中部增加L/S的内线。涡量矢量的纵向分量的估计为纵向涡旋的路径和强度等特性提供了新的信息。对涡量矢量的另外两个分量的进一步分析证实，在L/S等人的例子中，涡旋相互作用导致涡旋强度的突然丧失，但与边界的相互作用很弱。另一方面，在L/S*1的情况下，涡轴发生改变。下一步考虑的是在控制体积上积分的涡量输运方程，以求出涡量通量。控制体积的选择使得在任何流向位置都只能在内部发现一个涡流。小跨度周期导致涡度通量变化较大。另一方面，大跨度周期导致涡量通量逐渐减小，但在回弹点处涡轴的变化会产生微小的变化。较少

The interaction between a turbulent boundary layr and longitudinal vortex arrays introduced in the free stream has been investigated experimentally in order to clarify the effect of this interaction on the structure of the vortices and the boundary layr, respectivly. The spanwise periodic longitudinal vortex arrays are artificially generated in a free stream. One of the parameters, spanwise periodicity of longitudinal vortices L/S (L denotes the spanwise distance between neighboring airfoils, S the airfoil span), rules both magnitude an streamwise path of secondary vortices caused within the turbulent boundary layr. Intermittency factor profiles revealed the effect of pairs of counterrotating secondary flows which showed the downwash flow for the midspan of the airfoil, and conversely, the upwash flow for the center slice of neighboring airfoils. Intermittency factors are strongly affected by the spacing between neighboring airfoils. The value of the intermittency factor decreases in t … More he inner layr with increasing L/S at the midspan of the airfoil. The estimation of the longitudinal component of vorticity vector brings new information about the longitudinal vortex characteristics, like path and strength. A further analysis of the other two remaining components of vorticity vector confirm the fact that, in the case of L/S<1, the vortices interact with each other leading to an abrupt loss of vortex strength but the interaction with the boundary is very weak. On the other hand, in the case of L/S*1, the vortex axis changing occurs. The next stage considered was the vorticity transport equation integrated over a control volume in order to find the vorticity flux. The control volume has been chosen so that at any streamwise location only one vortex should be found inside. The small spanwise period leads to high variations of the vorticity flux. The large spanwise period, on the other hand, leads to a steadily decreasing vorticity flux except for a slight variation that is produced by the effect of the vortices axis changing at the rebounding points. Less