Previous investigators have shown that the discharge coefficient of circular orifices may be markedly reduced if located in a rotating disk. The thesis confirms the fact that orifice velocity and the pressure differential across the rotating disk are parameters affecting the discharge coefficient. In addition, fluid (air) density and orifice configuration were found to have a large effect on the discharge coefficient of rotating orifices. Disk thickness was not found to have an appreciable effect. The explanation for these effects is that the fluid enters the rotating orifice at an angle, which in turn decreases the orifice jet area. (Author).