An Experimental Facility to Generate Homogeneous Isotropic Turbulence*

We designed an experimental apparatus that generates homogeneous isotropic turbulence (HIT) to be used in fundamental studies to isolate the role of turbulence in complex flows and quantify its role in processes such as ice melting, flocculation, diffusivity and mixing. Inspired by the work of Bounoua et al. (2018), twenty synthetic jets are placed symmetrically around the tank exterior. We control the jets via the “random” forcing algorithm of Variano and Cowen (2008) to direct momentum to the center of the tank where a core of symmetric HIT absent mean flow is created. 

Particle image velocimetry (PIV) is used to measure turbulent flows within the experimental tank. Statistical analysis of PIV data provides mean and turbulent velocities, turbulent kinetic energy, spectra, integral scales, dissipation, Kolmogorov length and time scales, and the Taylor scale Reynolds number. The new facility required testing of a variety of parameter combinations of the jet forcing algorithm and pump outlet conditions including jet voltage, on time, and percentage of active jets to create an ideal turbulent environment. Initial measurements were completed to determine the length of an individual jet, varying voltage and on-time to inform HIT generation using the jet array.