Microfluidics is a technology where application span the biomedical field and beyond. Single cell analysis, tissue engineering, capillary electrophoresis, cancer detection, and immunoassays are just some of the applications within the medical field where microfluidics have excelled. The development of microfluidic technology has lead to novel research into fuel cells, ink jet printing, microreactors and electronic component cooling areas as diverse as food, pharmaceutics, cosmetics, medicine and biotechnology have benefited from these developments. Since laminar flow is prevailing at most flow regimes in the micro-scale, thorough mixing is a challenge within microfluidics. Therefore, understanding the flow fields on the micro-scale is key to the development of methods for successfully microfluidic mixing applications.