Effective kinematic viscosity of turbulence in superfluid He-4

Using superfluid helium II for the study of grid turbulence has many advant ages. He II has the lowest kinematic viscosity of any known substance, enab ling large Reynolds numbers to be achieved in a relatively small apparatus. In addition, the resolution of second sound attenuation measurements provi des insights into the decay of turbulence behind a grid. From measurements of this decay, we report preliminary experimental observations pertaining t o the effective kinematic viscosity of superfluid turbulence. We also provi de a better interpretation of the relation between second sound attenuation measurements and vorticity. (C) 2000 Elsevier Science B.V. All rights rese rved.