Boundary-Layer Transition Affected by Surface Roughness and Free-Stream Turbulence
Boundary-Layer Transition Affected by Surface Roughness and Free-Stream Turbulence
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DOI：
10.1115/1.1906266
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发表时间：
2005-05
影响因子：
2
通讯作者：
S. Roberts;M. Yaras
中科院分区：
文献类型：
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作者：
S. Roberts;M. Yaras
我们提出了记录表面粗糙度和自由流湍流对边界层过渡影响的实验结果。实验在平面上进行，在平面上施加与低压涡轮叶片吸力侧相似的压力分布。测试矩阵包括五种粗糙度条件的变化，三种自由流湍流强度（约0.5%，2.5%和4.5%），两种流动雷诺数分别为350,000和470,000。研究中考虑的这些参数范围是低压涡轮的典型参数，导致了附流和分离泡过渡。本文的重点是分离-气泡过渡，但也给出了在高粗糙度和自由流湍流条件下发生的少数附加流测试用例，以确保测试矩阵的完整性。在此基础上，量化了表面粗糙度对过渡起始位置和过渡速率的影响，并建立了这些影响对自由流湍流的敏感性
We present experimental results documenting the effects of surface roughness and free-stream turbulence on boundary-layer transition. The experiments were conducted on aflat surface, upon which a pressure distribution similar to those prevailing on the suction side of low-pressure turbine blades was imposed. The test matrix consists of five variations in the roughness conditions, at each of three free-stream turbulence intensities (approximately 0.5%, 2.5%, and 4.5%), and two flow Reynolds numbers of 350,000 and 470,000. The ranges of these parameters considered in the study, which are typical of low-pressure turbines, resulted in both attached-flow and separation-bubble transition. The focus of the paper is on separation-bubble transition, but the few attached-flow test cases that occurred under high roughness and free-stream turbulence conditions are also presented for completeness of the test matrix. Based on the experimental results, the effects of surface roughness on the location of transition onset and the rate of transition are quantified, and the sensitivity of these effects to free-stream turbulence is established