This work aims to advance the understanding of rotational dynamic filtration by investigation of the counter pressure generated by rotation. The counter pressure was experimentally evaluated with a series of experiments. The experimental conditions were varied by using mixtures of water/ethanol, different module geometries, various permeate flows, and rotational speeds for a total of 416 experiments. In addition computational fluid dynamic (CFD) simulations of the experimental setup were performed, leading to a better understanding of the experimental results. The results were assessed with a simplifying engineering model. It was demonstrated, that the experimental counter pressure diverges from the theoretical values. The experimental results suggest that a velocity factor should be included in the equation for counter pressure in rotating membrane systems. This finding was supported by evaluation of the CFD simulations, where the velocity factor also was found to diverge from theory. The study of module geometries also indicates that there is a small impact from geometry of the housing on the counter pressure, suggesting a need to determine the velocity factor for each system. This study provides new information on the influence of geometry and operational conditions on the counter pressure in rotating systems, a key parameter in the design and operation of such units.