DECAY OF VORTICITY IN HOMOGENEOUS TURBULENCE

We report on observations of turbulent behavior made without requiring the use of Taylor's ''frozen turbulence'' hypothesis. Initially, a to wed grid generates homogeneous turbulence of grid Reynolds number of o rder 10(5) within a stationary channel filled with helium II. The subs equent decay in time t of the line density of quantum vortices is meas ured by second sound attenuation, and the associated rms vorticity ome ga follows the behavior expected of a classical fluid with omega is si milar to t-3/2, consistent with the notion of a coupled turbulent stat e of helium II. This technique also yields the time dependence of the Kolmogorov microscale.