Some numerical experiments on particle-particle and particle-wall interactions under compensated gravity

In this study a numerical method is presented which can be very useful for investigations considering particle-particle or particle-wall interactions. The system of equations solved consists of the conservation of mass, momentum, and energy. The complicated geometries are approximated by using overlapping grids. In this method one relatively coarse major grid for the discretization of the whole computational domain is generated. The flow around the particles is then resolved by minor meshes which are adjusted to the particle geometry by the help oj curvilinear coordinates. The system of equations is solved using a finite-volume method for the discretization. In particular two rigid particles which are fixed on a wall are investigated. The results show the dependence of drag, lift, and Nusselt number from the particle distance and Reynolds number. Flows in which different phases or even components are present play an important role in a wide range of processes not only of scientific but also of technical interest. This is also the case in gravity compensated flows. The migration of bubbles/droplets, the transport of multiphase media in pipes, and particle transport due to electrophoreses are only a few examples for typical processes which are considered in the present extensively. Unfortunately, experiments are very expensive and suitable theoretical methods are not often available.