Behavior of settling inertial particles in a differentially heated cubic cavity at moderate Rayleigh number

This study is related to the transport of inertial particles in a differentially heated cubic cavity. Three moderate values of the Rayleigh number Ra = 2×10⁸, 4×10⁸, 7×10⁸ are considered. There is no back reaction from the particle on the flow, i.e., one-way coupling. Small (d = 15μm), intermediate (d = 35μm), and large (d = 75 μm) sizes of particles are used to study the particle behavior. The particles are influenced by two forces, the drag and gravity force. From our simulations, we observed that a large fraction of smallsized particles follow the flow motion and they are not significantly affected by gravity, remaining suspended in the flow. On the other hand, large-sized particles quickly settle down toward the bottom wall under gravity and are deposited at the bottom wall. Owing to this difference, particle distribution for small particles and large particles is quite different. Small particles tend to accumulate near a particular region near hot and cold walls, while the particle depletion region is observed in the core region in a particular pattern. Large particles are almost uniformly distributed. Detailed mechanisms are discussed using the flow field and particle response characteristics.