A Short Review on the Preferential Concentration of Particles in Fluid Flow

Particle laden fluid flows are important in many fields of application such as environmental, chemical, astrophysical, and biological flows. They are examples of multicomponent fluid flow where the dispersed component is transported within a carrier fluid, and the dynamics of the flow are mostly dictated by the carrier fluid. The dispersed phase generally consists of particles such as droplets, bubbles, sediments, or nanoparticles while the carrier phase is typically water, oil, and chemical and biological liquids. Preferential concentration is an important characteristic of such multicomponent fluid flow which is defined by a higher density of particles in local regions of flow based on local acceleration, vorticity, strain, and pressure. Due to the intrinsic challenges of dealing with turbulence, mixing, particle tracking, and inter-and intra-component interactions, these flows are complicated to model. Based on the mass ratio of the particles to the fluid, the particles exhibit different preferential concentration patterns. In this article, experimental and numerical works on the preferential concentration of dispersed particles in different fluid flow problems are reviewed and discussed.