Active chaotic mixing in a channel with rotating arc-walls

An active inline mixer, called Rotating Arc-Wall mixer (RAW), suitable for flows at low Reynolds number and high P\'eclet number, is studied. The forcing protocol, imposed by three rotating circular arc-walls, time periodic. We use simple phenomenological arguments to estimate heuristically the mixing efficiency with two nondimensional control parameters: frequency of strength cross flow relative primary flow. validity limitations proposed conditions are explained transport mechanisms in beneficial role chaotic advection highlighted.