Mixing enhancement using chaos theory in fluid dynamics: Experimental and numerical study

Abstract In the present study, the effect of chaotic advection on mixing of laminar flow was experimentally and numerically investigated. The mixer consisted of two rotors with a circular cross-section and a cylindrical stator. Rotational speed of the rotors could be controlled with time which was the main factor for creating chaotic advection. Experimental results showed that, when the rotors rotated at a constant rotational speed, secondary flows were created in the mixer to prevent the distribution of fluid particles on the mixer surface. However, by applying sinusoidal perturbation to the speed of the rotors, the weakly mixed regions disappeared over time and the fluid particles were well distributed on the mixer surface. The streamlines inside the mixer were also calculated and examined using numerical simulations for the constant and variable rotational speed of the rotors. Poincare sections indicated that when the rotational speed of the rotors was variable, the flow inside the mixer was sensitive to the initial conditions, which is one of the important characteristics of the chaotic flow.