Unsteady Boundary-Layer Transition in Flow Periodically Disturbed by Wakes
Unsteady Boundary-Layer Transition in Flow Periodically Disturbed by Wakes
复制标题
受尾流周期性干扰的流动中的不稳定边界层转变
DOI：
10.1115/92-gt-283
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发表时间：
1992
期刊：
影响因子：
--
通讯作者：
U. Orth
中科院分区：
文献类型：
--
作者：
U. Orth
涡轮机械叶片上的边界层是在周期性地受到上游叶片叶栅尾迹扰动的流动中形成的。这些尾迹对层流-湍流边界层过渡有显著影响。为了研究这些影响，使用热线探针在流动中的板的边界层内进行了详细的速度测量，流动中周期性地受到横向移动的杆产生的尾迹的干扰。测量结果采用集合平均技术进行评估。结果显示了尾流扰动如何进入边界层并导致湍流斑块，该斑块逐渐增大并被带到下游。在有利压力梯度下，尾迹湍流引起的转捩比线性稳定性理论预测的要早得多。在两个尾迹之间，观察到的层流平静区远远超出了未受干扰的边界层已经湍流的点。ASME版权所有©1992
Boundary layers on turbomachinery blades develop in a flow which is periodically disturbed by the wakes of upstream blade cascades. These wakes have a significant effect upon laminar-turbulent boundary-layer transition. In order to study these effects, detailed velocity measurements using hot-wire probes were performed within the boundary-layer of a plate in flow periodically disturbed by wakes produced by bars moving transversal to the flow. The measurements were evaluated using the ensemble-averaging technique. The results show how the wake disturbance enters the boundary-layer and leads to a turbulent patch, which grows and is carried downstream. In favorable pressure gradients, transition due to wake turbulence occured much earlier than predicted by linear stability theory. Between two wakes, laminar becalmed regions were observed far beyond the point at which the undisturbed boundary-layer was already turbulent.Copyright © 1992 by ASME