Composing chaos: An experimental and numerical study of an open duct mixing flow

By using a programmed sequence of boundary motions to introduce flow reorientation to a steady, laminar axial flow in an open duct, we develop a novel device to investigate and exploit chaotic advection of viscously dominated (low Reynolds number) flows. The design and operation of the Rotated Arc Mixer (RAM) is discussed. Among other things, the RAM can effect good continuous mixing of viscous materials without use of any internal elements; moreover, the RAM has several control parameters to tune the chaotic advection, making it flexible for applications and theoretical developments. Numerical methods to discover the robust parameter regions where chaos covers the entire flow domain, and how these parameters change with fluid properties is also discussed. Poincaré sections, dye advection and residence time calculations are presented for Newtonian and non‐Newtonian fluids. Experiments, including advection field, velocity field and residence‐time measurements, confirm all aspects of the device for Newtonian fluids.