STABILITY OF TAYLOR-COUETTE FLOW IN SUPERFLUID-HELIUM IN THE PRESENCEOF SUPERFLUID VORTEX LINES

Taylor-Couette flow between two coaxial cylinders with a rotating inne r cylinder and a fixed outer cylinder has been investigated in the tem perature range from 1.45 to 2.15 K. The density of quantized vortex li nes in the gap between the cylinders was measured by analyzing the dam ping of azimuthal second-sound resonances. Increasing the angular velo city of the inner cylinder the first appearance of quantized vortices was detected at a critical angular velocity of OMEGA0. The onset of th e Taylor instability occurred at a critical Rcynolds number Re(c) whic h appeared to be temperature dependent. In agreement with theoretical predictions the experimental results show that the presence of quantiz ed vortex lines strongly influences the stability of the flow field.