Particle Tracking in High Reynolds Number Turbulent Flows

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In this research program the silicon strip technology from High Energy Physics detectors is further developed for three dimensional particle tracking. Fundamental questions about Lagrangian properties of turbulence are unanswered, and our ability to test theoretical models is very limited. Important unsolved problems include statistics of the fluid particle acceleration, inertial range scaling of the Lagrangian structure functions, and n-particle turbulent dispersion. This new technology allows to follow up to four particles in three dimensions at sufficient spatial and temporal resolution to provide the facility to measure single and multiple particle Langrangian statistics in the dissipation and interial range of high Reynolds number turbulence. Simultaneously, new ways are developed to generate very high Reynolds number isotropic and homogeneous turbulence in flows with no mean velocity. These measurements will provide much needed data to compare with theoretical predictions and may trigger new directions in theoretical research. In addition, they will give important information needed to address problems of turbulent diffusion in many processes ranging from turbulent combustion to pollutant transport in the atmosphere. It also promises the continued development of high speed strip detectors as a general purpose tool which can be used for many measurements where a weak light streak has to be followed in real time.