Subgrid-Scale Modeling of the Scalar Variance in Large Eddy Simulation

Turbulence is characterized by chaotic changes in pressure and flow velocity. Better understanding of turbulent flow will help in the understanding of air movement including wind currents, dissipation of pollutants and storm formation. Although much research has been done on the nature of turbulence in the atmosphere, little has been centered on humidity turbulence in supersaturated conditions. In an effort to better understand LES and the closure problem for turbulence fluctuations of supersaturation, temperature was monitored within a pi chamber while turbulence was being induced. Several measurements were made with a thermistor array at various temperatures and spacings. The data gathered will be used for a priori testing. Two models, a scale-similarity model and a gradient model, will be tested with the data gathered. This testing will further scientists’ understanding of the humidity turbulence present during the formation of clouds.