As I've been reading up on fluid mechanics recently, I've discovered several different molecular models which attempt to explain heterogeneous fluid flow from a molecular level. Classical fluid mechanics assumes that hard body approximation- that atoms are hard spheres knocking into each other. In dense fluids, however, the atoms would be close enough that we cannot ignore quantum effects from overlapping charge clouds. The two models I stumbled across are the surface charge model and the potential at a distance model. There is a database (COSMO) that averages the charge in a molecule and converts it to a surface charge on a solid conductor. Using Maxwell equations this model could describe the potential distribution within a bounded region of fluid. This model is not simple, and therefore I suspect that there is a more fundamental model which is simpler and more accurate. The other model I read about was the potential at a distance model. To make a heterogenous fluid, superimpose different atoms in a dielectric medium and calculate the multipoles of each atom. This model seems more elegant, and I would love to compare it against empiracle evidence. Anyhow you can skip to here if you don't want to read. I want to start a conversation about building a fundamental model of fluid mechanics using everything we have learned in the past 100 years. The Rayleigh-Plesset equations are still prevalent, and Lord Rayleigh died in 1919. Post your thoughts, whatever they may be.