Four regimes of decaying grid turbulence in a finite channel

Attenuation of second sound in helium II has been used to observe up to 6 o rders of magnitude of decaying vorticity displaying four distinctly differe nt regimes of decaying grid turbulence in a finite channel. A purely classi cal spectral model For homogeneous and isotropic turbulence describes most of the decay of helium II vorticity in the temperature range 1.2 < T < 2 K. The four regimes switch successively as the energy-containing and dissipat ive Kolmogorov length scales gradually grow during the decay, finally both bring saturated by the size of the channel.