National Aeronautics and Space Administration

Glenn Research Center

Dr. Gregory Zimmerli

On June 13, 2012, by Dr. Gregory Zimmerli presented a talk on turbulent fluctuations. The lecture was about the work that was done back in 2006 when his team used dynamic light scatter technique (DLS) in turbulent flows. DLS allowed tracking of well-defined particles through incident light. The objective for the project was to conduct a two point velocity correlation DLS measurements in turbulence data and compare to hot wire data. In order to do this, the project team created a sealed chamber that led into a vent system that cleaned out any vortices in the smoke flow. The delta V was measured for all data sets. It was found that the decay was faster the longer the length scale. The data was also plotted using the Taylor and Kolmogorov parameters. Both methods showed signs of self-similarity no matter the wind speed. For turbulent fluctuations it was found that the Taylor parameters cleaned up the data the best so that all the data series fit on the one curve. This was supported by applying this slick technique to data collected by a different data form Australia.