Resolving the Structure of Turbulence in Rough Wall Channel Flows Using 3D, Time Resolved, Multiscale Velocity Measurements

PI: Katz， joseph提案号：1438203提议的研究旨在探索湍流是如何产生和持续接近固体边界的。它将使用非常精确的实验结果来阐明能量在湍流中不同区域之间传递的方式。因此，这项研究将允许为存在固体壁的流动系统设计开发正确的模型，而固体壁实际上是工业和环境中最常见的湍流情况。教育活动涉及研究生和本科生，以开发和实施拟议的测量系统。巴尔的摩市的高中生也计划在PI工作一年的活动。作为他们必修的研究实习的一部分。这项工作将研究粗糙度的高度、波长、空间排列和均匀性如何影响漩涡的产生、它们的时间演变、它们与远离壁面的漩涡的相互作用，以及这些相互作用对湍流统计的影响。提出了一种相当全面和不琐碎的实验方法：三维时间分辨层析PIV将解决壁面附近的小尺度湍流，而数字全息显微镜（DHM）将同时观察远离壁面的大尺度结构。联合TPIV-DHM仪器可分辨3.5个数量级的长度尺度。

PI: Katz, JosephProposal Number: 1438203 The proposed research aims to explore how turbulence is generated and sustained close to solid boundaries. It will use findings from very accurate experiments to clarify the way that energy is transferred in turbulent flows between the different regions of the flow. As such, this research would allow the development of correct models for the design of flow systems where solid walls are present, which are in fact the most common cases of turbulent flows in industry and the environment. Educational activities involve graduate and undergraduate students for the development and implementation of the proposed measurement system. There are also activities planned for Baltimore City high-school students to work yearlong in the PI?s laboratory as part of their required Research Practicum.This work will investigate how the roughness height, wavelength, spatial arrangement and uniformity, affect the generation of vortices, their evolution in time, their interactions with vortices away from the wall, and impact of these interactions on turbulence statistics. A rather comprehensive and non-trivial experimental approach is proposed: A 3D time-resolved tomographic PIV will resolve small-scale turbulence near the wall, while digital holographic microscopy (DHM) will be used to simultaneously observe the large scale structures away from the wall. The combined TPIV-DHM instrument would resolve 3.5 orders of magnitude of length scales.