Simulation and eigenmode analysis of advective-diffusive transport in micro-mixers by the diffusive mapping method

摘要: Advective–diffusive transport in microflows is studied by means of the diffusive mapping method, a recent extension method Gorodetskyi et al. (2012. Phys. Fluids 24) that includes molecular diffusion. This greatly expands application area technique and makes powerful concepts eigenmode decomposition spectral analysis scalar accessible to an important class flows: inline micromixers with The staggered herringbone micro-mixer adopted as prototypical three-dimensional micro mixer. Simulations are close agreement experimental observations literature expose strong impact diffusion on transport. Diffusion enables crossing Lagrangian barriers thus smoothens concentration gradients accelerates homogenization. Spectral matrix reveals this already occurs modal level which individual eigenmodes progressively smoothen spread out across stronger Concurrently, corresponding eigenvalues diminish fundamentally alter mixing process invariably causing homogenization, irrespective flow structure. happens faster exhibits earlier emergence dominant structures may still affect properties flows comprising both islands chaotic seas typically result richer set compared cases global chaos.