Mixing in turbulent flows

在自然界和人造世界中，湍流都是常态(层流是个例外)。它们的基础是它们快速混合质量、动量或能量的能力--这是一种广泛的过程的基础，包括空气动力学、气象学、燃烧和环境污染物扩散。本提案的主要目的是通过原创性、创新性的研究，对湍流内的混合过程提供新的见解。为此，我的长期目标有四个：1)进行仔细的、最先进的实验，为湍流混合提供新的视角；2)培训本科生、硕士和博士水平的HQP；3)构思新的实验方法和工具，开发有利于我的研究小组和整个湍流社区的创新技术；4)为那些模拟和模拟湍流的科学家和工程师提供可靠的详细、高质量的湍流测量数据集。因此，他们可以验证他们的模拟/模型。*为了实现这些长期目标，本申请提出了一套与湍流中标量(例如，温度、化学物质浓度)混合有关的补充项目。这五个研究项目涉及：1)背景湍流对自由剪切流动混合的影响的量化，2)高雷诺数和Péclet数混合，3)湍流流动中多标量的同时混合，4)多孔表面/边界上的标量扩散，5)冰雪表面上湍流换热的影响。这项研究的结果将与燃烧、环境污染物扩散和气候模拟领域的工作人员直接相关。该研究计划还将培训HQP在湍流和一般热流体方面的知识，为当地的航空航天、水电、汽车等行业提供熟练的专业人员。*鉴于我的实验室在过去5年收购了两个新的实验设备(包括一个新的风洞)，以及新型仪器的开发(使新的精密测量成为可能，世界上很少有研究小组能够做到这一点)，现在将可能取得显著的进展。此外，上述研究的结果将回答有关湍流混合的重要悬而未决的问题。然后，应将所获得的知识应用于与能源和环境有关的学科的技术改进(例如，提高燃烧器效率、改进政府对环境污染物扩散的影响评估模型)。

In both nature and the man-made world, turbulent flows are the norm (laminar flows being the exception). Fundamental to them is their capacity to rapidly mix mass, momentum or energy – an attribute that underlies a wide range of processes, including aerodynamics, meteorology, combustion, and environmental pollutant dispersion. The main goal of the present proposal is to provide novel insights into the mixing process within turbulent flows by way of original, innovative research. To this end, my long-term objectives are four-fold: 1) to undertake careful, state-of-the-art experiments that will provide new perspectives on turbulent mixing, 2) to train HQP at the undergraduate, master's and doctoral levels, 3) to conceive of new experimental methods and tools for the development of innovative technologies benefitting both my research group and the general turbulence community, and 4) to provide reliable datasets of detailed, high-quality measurements in turbulent flows to those scientists and engineers who simulate and model turbulence, so they can validate their simulations/models.****** To accomplish these long-term objectives, the present application proposes a complementary set of projects relevant to the mixing of scalars (e.g., temperature, chemical species concentration) in turbulent flows. The five research projects pertain to: 1) quantification of the effect of background turbulence on the mixing within free-shear flows, 2) mixing at high Reynolds and Péclet numbers, 3) simultaneous mixing of multiple scalars within turbulent flows, 4) scalar dispersion over a porous surface/boundary, and 5) the effect of turbulent heat transfer above snow and ice surfaces. The results of this research will be of immediate relevance to workers in the fields of combustion, environmental pollutant dispersion, and climate modelling. The research program will also train HQP in turbulent flows, and thermofluids in general, supplying skilled professionals to the local aerospace, hydropower, automotive, etc. industries.****** Given the acquisition in the last 5 years of two new experimental facilities in my laboratory (including a new wind tunnel), and the development of novel instrumentation (enabling new sophisticated measurements of which few research groups worldwide are capable), notable advances will now be possible. Moreover, the results of the above studies will answer important unresolved questions about turbulent mixing. The knowledge obtained should then be applied to technological improvements in disciplines related to energy and the environment (e.g., increased combustor efficiencies, improved governmental impact assessment models of environmental pollutant dispersion).