U.S.-France Cooperative Research: Concentration Flux Measurements and Modeling of Scalar Transport in Bounded Turbulent Shear Flows

这项为期三年的奖项为美法合作研究来自线和点源的被动标量污染物在湍流边界层壁上的扩散提供了支持。研究人员将对标量场的行为和预测进行理论和实验研究，因为它与城市空气质量有关。由马里兰大学的詹姆斯·M·华莱士和法国里昂中央学院流体力学和声学实验室的米歇尔·艾罗领导的研究小组参与了这项合作。实验将结合光学测量方法：粒子图像测速仪和Mie散射浓度测量，以获得流动中的标量通量。此外，研究人员将检验一个新的非局部标量通量模型对实验工作中考虑的相同流动条件的预测能力。理论模拟和实验相结合将促进对标量场行为和预测的理解，从而减少城市空气质量模拟中的一个主要不确定性来源。美国研究人员为这次合作带来了湍流边界层和标量弥散研究方面的专业知识。法国在PIV/Mie散射技术方面的专业知识以及适应PIV/Mie散射测量技术要求的特殊风洞对此进行了补充。

This three-year award provides support for US-France cooperative research on studies of the dispersion of passive scalar contaminants from line and point sources at the wall of turbulent boundary layers. The investigators will conduct theoretical and experimental studies into the behavior and prediction of scalar fields as it relates to urban air quality. The collaboration involves research groups led by James M. Wallace of the University of Maryland and Michel Ayrault of the Fluid Mechanics and Acoustics Laboratory of the Ecole Centrale in Lyon, France. The experiments will combine optical measurement methods: Particle Image Velocimetry and Mie scattering concentration measurements in order to obtain scalar fluxes in the flows. In addition, the investigators will examine the predictive capabilities of a new non-local scalar flux model for the same flow conditions considered in the experimental work. The combined theoretical modeling and experiments will advance understanding of the behavior and prediction of scalar fields, thus reducing a principal source of uncertainty in urban air quality modeling. The US investigators bring to this collaboration expertise in studies of turbulent boundary layers and scalar dispersion. This is complemented by French expertise in PIV/Mie scattering techniques and a special windtunnel adapted to accommodate the requirements of the PIV/Mie scattering measurement techniques.