It is now widely acknowledged that the simulated microgravity environment of NASA-designed rotating-wall vessels (RWVs) offers great advantages for three-dimensional growth of mammalian cells. In the rotating-wall vessel, the solid body rotation is accomplished by horizontally rotating a vessel, which consists of a cylinder or two concentric cylinders and is completely filled with culture medium, at a constant rotational speed. Mixing and shear forces in the RWV are due to the microcarriers’ motion in the fluid, and the contact that the microcarriers occasionally make with the wall and each other . Therefore, the motion of microcarriers in the rotating flow is of interest and important in the design of the rotating-wall vessel bioreactors and in the guiding of RWV cell culture experiments under optimal operating conditions.
Predictions of a single microcarrier migration inside the RWV have been described in our previous study . However, the particle-wall and the particle-particle interactions were not considered. In this study, we numerically investigate the motion of microcarriers with the effects of the collisions under consideration.