This paper presents an experimental and numerical study of the sweeping jet oscillation frequency which is a crucial parameter for effective separation control. Measurements of the time-resolved static pressure are made in the feedback channels using high-frequency pressure transducers. Experiments are performed for eight different inlet mass flow rates (from 1g/s to 8 g/s). The effects of geometry scaling are examined for the halfand double-size of the baseline actuator. The results reveal a relationship between the oscillating frequency and the inlet mass flow rate and demonstrate a linear trend of the Strouhal number versus the inlet Mach number for all the geometries. The experimental results are compared toresults obtained from numerical simulations using Ansys Fluent v17.2 software.A high correspondence is found between experimental results and numerical data from computationally inexpensive 2D-URANS simulations. This result opens possibilities of using these simple numerical models to perform extensive studies of the geometric parameters of the sweeping jet actuator in the future.