Induced and spontaneous phase diffusion in the Taylor-Couette flow

The reaction of the Taylor-Couette flow system to an external phase perturbation, as well as the phenomena occurring in spontaneous phase perturbations were investigated. This system represents the flow of an incompressible fluid between two concentric, rotating cylinders. The parameter describing the flow state is the Reynolds number. The influence of the final vortex size on the stability behavior of the Taylor vortex was clarified. The vortex displacement following an induced phase perturbation very closely obeys an exponential law. The experimental time constant of the vortex system phase change confirms the theoretical prediction, and allows to define a diffusion coefficient for the vortex system phase behavior. Theoretical predictions concerning this diffusion coefficient were experimentally verified, and empirical formulas for parameter dependence were established. Possible excitation mechanisms for the discovered Snaily mode are discussed.