A flow source for the study of quantum turbulence in superfluid

A flow source has been developed to generate turbulent superfluid flows in channels equipped for detection of quantised vortices. The source consists of a motor driven low temperature compressible volume capable of pushing or sucking superfluid 4He into a flow channel. Detection is based on the attenuation of second sound caused by the presence of quantised vortex lines in the turbulent flow. In this paper we present the technical details of the apparatus, along with some raw data obtained during the first successful low temperature test. The test has been performed using the source to generate a flow into a channel whose ends have been blocked by superleaks to allow for the inflow and outflow of the superfluid component of helium only. This technique enables to determine the areal density of quantised vortex lines in the temperature range 1.3 to 2.1 K, with well controlled flow velocities between 0.01 and 30 cm/s