Experimental results on the structure of hydronamic turbulence in accretion disks

The Princeton Hydrodynamic Turbulence Experiment (HTX) is a Taylor-Couette device with a variable speed rings at the axial boundaries and the ability to perturb quiescent flow regimes via a pump system. The experiment is designed to quantify purely hydrodynamic effects present in accretion disks, as well as study boundary effects, such as Ekman circulation and Stewartson layers, in Taylor-Couette systems. The results of this experiment supplement those of the Princeton MRI experiment, a Taylor-Couette device filled with a GaInSn fluid, which was designed to study the magnetorotational instability (MRI), the current explanation for observed accretion rates in accretion disks. The main diagnostic in HTX is a laser doppler velocimetry (LDV) system capable of correlating azimuthal and radial velocity measurements. We present recent experimental results on the lifetimes of turbulence forced by direct perturbations as a function of dimensionless rotational shear ($q$) as well as an autocorrelation analysis of the azimuthal velocity fluctuations in the quasi-Keplerian regime.