Collisional particle-phase pressure in particle-fluid flows at high particle inertia

Particle-phase pressure has to be considered in two-fluid models describing particle-fluid flows, and is important for the stability of such flows. However, most research so far has focused on its dependence on shear-induced particle velocity fluctuations. This Brief Communication proposes a simple model to predict collisional particle-phase pressure at high particle inertia due to microscopic particle number and velocity fluctuations in the absence of any large-scale shearing. The results are in good agreement with the experimental data of Zenit [J. Fluid. Mech 353, 261 (1997)]