Experimental investigations of critical roughness heights and roughness-induced laminar-turbulent transition in a laminar boundary layer

层流边界层中临界粗糙度高度和粗糙度引起的层流-湍流转变的实验研究

• 批准号: 250568929
• 负责人: Professor Dr.-Ing. Ulrich Rist
• 金额: --
• 依托单位: Institut für Aerodynamik und Gasdynamik (IAG)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2014
• 资助国家: 德国
• 起止时间: 2013-12-31 至 2017-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/250568929?language=en
• 关键词: Experimental; investigations; critical; roughness; heights

The influence of wall roughness on laminar-turbulent transition has just attained increasing relevance in connection with efforts on drag reduction for boundary layers. To back up theoretical investigations which are pursued in several European countries, there is a clear need for an experimental investigation to validate the most recent developments in linear stability theory and their usefulness for predicting the critical roughness height in a laminar boundary layer. The present experiments are intended to yield insights into the acting mechanisms and to check and validate assumptions and results of the theory. A very unique low-speed water channel facility with carefully controlled low-turbulence level is available for the present research. Flow visualizations, hot-film measurements, investigations with linear stability theory and PIV-measurements will be performed at the University of Stuttgart. Base-flow data, results of 3D global instability, and DNS data will be contributed by international partners from KTH Stockholm, Sweden and ENSAM (ParisTech), Paris, France. In return, the experimental results will be shared by all three research groups. This offers a lot of synergies since the requested DFG-funding is restricted to the experimental work.

壁面粗糙度对层流-湍流过渡的影响刚刚在边界层减阻方面得到越来越多的关注。为了支持在几个欧洲国家进行的理论研究，显然需要进行实验研究，以验证线性稳定性理论的最新发展及其在预测层流边界层临界粗糙度高度方面的有用性。目前的实验旨在深入了解作用机制，并检查和验证理论的假设和结果。一个非常独特的低速水道设备，具有精心控制的低湍流水平，可用于本研究。流动可视化、热膜测量、线性稳定性理论研究和piv测量将在斯图加特大学进行。基础流数据、3D全球不稳定结果和DNS数据将由瑞典斯德哥尔摩KTH和法国巴黎的ENSAM （ParisTech）的国际合作伙伴提供。作为回报，实验结果将由所有三个研究小组共享。这提供了很多协同效应，因为所要求的dfg资金仅限于实验工作。