Poincaré indices of rheoscopic visualisations
Poincaré indices of rheoscopic visualisations
Suspensions of small anisotropic particles, "rheoscopic fluids", are used for flow visualisation. By illuminating the fluid with light of three different colours, it is possible to determine Poincaré indices for vector fields formed by the longest axis of the particles. Because this vector field is non-oriented, half-integer Poincaré indices are …