A rotor blade for a wind turbine, to a wind turbine comprising a tower, a nacelle and a rotor, and also to a wind farm. The rotor blade comprises an inner blade section that extends from a rotor blade root in the longitudinal direction of the rotor blade, and a trailing edge segment, arranged on the inner blade section, for increasing the profile depth of the rotor blade along a section in the longitudinal direction of the rotor blade. The rotor blade has a pressure-side surface and a suction-side surface, which are each formed in certain regions by parts of the inner blade section and of the trailing edge segment. One or more air outlets and air inlets extending substantially in the longitudinal direction of the rotor blade are formed on both the pressure-side surface and the suction-side surface of the rotor blade, in the region of the trailing edge segment, said air outlets and air inlets being interconnected in a fluid-guiding manner. At least one covering element overlapping the at least one air outlet and by means of which the air outlet can be closed or opened is arranged on the suction-side surface.