Fluorescent Solution micro Capsules as Tracer Particles in Long-term Tracking of 3D Lagrangian Trajectories

Fluorescent solution microcapsules (diameter < 100 μm) have been invented as tracer particles suitable for the long-term tracking of 3-D Lagrangian trajectories in the rotating annulus fluid experiments. In more than 10% of the tracking experiments, the microcapsule was observed to follow the flow passively for more than 10 hours, at their maximum 18 hours.