Our technique of choice for complex fluid simulations on the mesoscale is Smoothed Particle Hydrodynamics (SPH). The advantage of the particle approach is that we can cleanly incorporate solid microparticles into the fluid simulations. We have undertaken extensive theoretical work to tailor SPH to multi-component fluids. The result is ‘Continuous Smoothed Particle Hydrodynamics’, or CSPH.

In SPH each blob contains only one component, but in CSPH the blobs can contain multiple components, which shift between blobs by diffusion. Our development of CSPH is crucial not only for modeling mixing of different fluids, but also for allowing components (like surfactants) to diffuse through a fluid at experimentally realistic low concentrations. Chemical interactions between blobs have been developed based on lattice fluid theory.