Management of the Turbulent Boundary Layer using the Strong Spanwise Deformation by a Pair of Streamwise Vortex

利用一对流向涡强展向变形管理湍流边界层

基本信息

批准号：
09650191
负责人：
OSAKA Hideo
金额：
$ 1.79万
依托单位：
YAMAGUCHI UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 1998
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09650191/
关键词：
Turbulent Boundary Layer A Pair of Streamwise Vortex Management (Control)Secondary Flow Spanwise Rate of Strain Interaction Process 干渉

项目摘要

The interaction process between a turbulent boundary layer and a pair of vortex introduced in the main flow has been examined experimentally. Both longitudinal vortex pair with "common-flow" down and "common-flow" up, were generated by a deltawing set * 8ﾟ angle-of-attack. The generator height was selected to provide a vortex which would be obtained the experimental parameters, such as GAMMA/U_1 delta_0 <1, GAMMA / utau delta_0 * 1 and d_0 / delta_0* 1( GAMMA : vortex circulation, U_1 : free stream velocity, delta_0 : initial boundary layer thickness, Utau : friction velocity, d_0 : vortex diameter). Isovels of mean vorticity and secondary flow vectors revealed a pair of streamwise vortex of which center located at the position inside 30% of wing span for both cases "common-flow" down and up. In case of common-flow up, streamwise vortex reduce faster after the investigation on vortex path and vorticity decay, and the effect of streamwise vortex on the boundary layer characteristics is limited to the spanwise local region. In both cases of common-flow up and down, however, mean velocity, turbulent intensity and Reynolds shear stress values are significantly altered near the location of vortex center. Each isovels of turbulent quantities are deformed at some slice between neighboring vortex due to the effect of the extra rate of strain. Wall shear stress at the spanwise center position' shows peak value in case of common-flow down, conversely minimum one in case of common-flow up due to the secondary flow effect. A discontinuity on three-dimensional separation line is not formed anywhere in spanwise slice. Local similarity evaluated with local scales does not establish in the inner layer in both cases of common-flow down and up. The effect of Reynolds normal stress difference on the streamwise vortex remaining is significantly large. In the next stage, turbulence management using a pair of streamwise vortex must be considered.

已经通过实验检查了湍流边界层和一对涡流之间的相互作用过程。这两对纵向涡流对与“ common-flow”下降和“ common-flow”上升，都是由Deltawing Set * 8 ﾟ攻击生成的。 The generator height was selected to provide a vortex which would be obtained the experimental parameters, such as GAMMA/U_1 delta_0 <1, GAMMA / utau delta_0 * 1 and d_0 /delta_0* 1( GAMMA: vortex circulation, U_1: free stream velocity, delta_0: initial boundary layer thickness, Utau: friction velocity, d_0:涡流直径）。平均涡度和二次流量向量的异卵形揭示了一对流向涡流的涡流，其中心位于两种情况下及向上的“ common-flow”下方的机翼跨度内部30％的位置。如果发生共同流量，流向涡流涡流和涡旋衰减后，流涡流降低了，并且流向涡流对边界层特性的影响仅限于Spanwise端区。然而，在这两种情况下，平均速度，湍流强度和雷诺剪切应力值在涡旋中心的位置附近都发生了显着改变。由于额外的应变速率的影响，每个湍流量的湍流量在相邻涡流之间的某个切片变形。在跨度中心位置处的壁剪应力在频率下降的情况下显示出峰值，相反，由于次级流动效应，通常会在公共流量上升高。三维分离线上的不连续性不会在Spanwise切片中任何地方形成。在两种情况下，局部尺度评估的局部相似性在两种情况下均未在内层中建立。 Reynolds正常应力差异对剩余的流向涡流的影响很大。在下一阶段，必须考虑使用一对流向涡流的湍流管理。