Motion of solid particles and flow visualization in Helium II

Abstract

Recent experiments have shown that it is possible to implement Particle Image Velocimetry (PIV) in liquid helium. However, to interpret the PIV data in the superfluid phase, it is necessary to understand how the particles are affected by the two components, the viscous normal fluid and the inviscid superfluid, as well as by the quantized vortex lines that may exist in the superfluid component. The chapter is supplemented by exercises aiming to assist the reader in better understanding this rapidly developing area of research.