The present disclosure relates to a rotary-cutting disk for a centrifuge. The rotary-cutting disk includes a disk-shaped base section adjoined by a tube-shaped section. Also included is at least one draining duct for a liquid phase in the base section, the draining duct extending at an acute angle from an inlet at an outer circumference of the base section and in a flow direction of a liquid phase. The at least one draining duct includes walls extending from the inlet to an outlet. At least one of the walls of the draining duct is at least partially or in sections contoured in a wave shape.