Physics of Mixing

Description and aim

Scope and challenges  Mixing of scalars (e.g. additives, nutrients, heat) by laminar flows is the common denominator in a wide variety of industrial and natural fluid systems of size extending from microns to hundreds of kilometers. Industrial examples range from mixing in the rapidly expanding field of micro-fluidics, encompassing applications as diverse as micro-electronics cooling, micro-reactors, “labs-on-a-chip” for molecular analysis and biotechnology and “smart pills” for targeted drug delivery, up to the mixing and thermal processing of viscous fluids via compact processing equipment. Examples in Nature include magma transport in the Earth’s mantle, dispersion of hydrocarbons in fractured rock as well as gas exchange in lung alveoli and distribution of blood-borne pathogens.

Profound insight into the mechanisms underlying laminar mixing – and ways to purposefully employ and control them – has, given its ubiquity in industry and Nature, great scientific, technological and societal relevance and is in fact imperative for further development of fluids-processing technology in, especially, sophisticated micro-fluidics applications and process engineering. Although this insight remains limited to date, important mathematical-physical approaches for the analysis and understanding of mixing in 3D laminar flows became available during the last decade. Moreover, both the advancement of measurement technologies to investigate 3D mixing in laboratory set-ups (such as Laser Induced Fluorescence, 3D Particle Tracking Velocimetry, micro Particle Image Velocimetry) and the rapid development of active and passive mixing elements for microfluidic devices opens the perspective for quantitative 3D mixing studies for industrial and microfluidic applications. Key challenges for facilitating advancement in this field are: developing a thorough understanding of laminar transport mechanisms in 3D realistic fluid systems, including (non-)Newtonian and viscoelastic fluids; their rigorous experimental validation; (further) development of 3D transport formalisms on the basis of principles from mathematical physics; their translation and integration into analysis and design strategies; (further) development of numerical and experimental methods for transport studies. To this end multi-disciplinary research initiatives are essential and an LC workshop in Leiden will surely facilitate such initiatives by bringing together colleagues from the different (multidisciplinary) fields and foster new (multi-disciplinary) collaborations.

Aim The workshop seeks to address the above challenges by providing a platform for (theoretical) physicists, mathematicians and engineers (experimentalists and numericists alike) for exchanging ideas and views on all relevant aspects of laminar mixing. Goals are communication of the key fundamental and practical issues, discussion of ways to tackle them and promotion of cross-disciplinary collaboration. This will be facilitated through keynote lectures by leading experts and (invited) contributed talks by senior and junior scientists.