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.

与边界层减少阻力的努力有关，墙壁粗糙度对层状驱动过渡的影响刚刚达到了越来越多的相关性。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层边界层中临界粗糙度高度的有用性。本实验旨在产生对作用机制的见解，并检查和验证理论的假设和结果。目前的研究可用一个非常独特的低速水通道设施，具有精心控制的低扰动水平。斯图加特大学将进行流动可视化，热膜测量，线性稳定性理论的研究和PIV测量。 基础流数据，3D全球不稳定结果和DNS数据的结果将由来自法国巴黎的KTH斯德哥尔摩，瑞典和Ensam（Paristech）的国际合作伙伴提供贡献。 作为回报，所有三个研究小组将共享实验结果。这提供了许多协同作用，因为所需的DFG资金仅限于实验工作。