Abstract: Using lab-scale mixing experiments to inform LES of stellar convection
The comparison between Large-eddy simulations (LES) and experimental data is problematic due to the inherent filtering of the LES data. Filtering techniques (Leonard 1974, Germano 1992, Klein 2018) can be applied, allowing for a better comparison between these data sets. The experimental data from the turbulent mixing tunnel (TMT) (Charonko, Prestridge 2017) are velocity and density fields of variable-density mixing conditions in a coflowing jet. This provides an excellent data set for testing filtering techniques as the sample size is large, the samples are high resolution, and variable density effects are tested. Containing 10,000 velocity and density fields per location, a subset of the TMT data is chosen to represent a low sample size data set. Filtering techniques are then applied to the sample set and the averages are compared. These techniques have application to validation of LES simulations and sub grid modeling efforts as the Reynolds stress from filtered vs non-filtered data are important. The jet conditions are relevant to high-shear and mixing regions at the edges of stellar convection zones, so the results can assist in determining the resolution effects on large LES calculations of these flows.