Provided is an aerodynamic structure for mounting to a surface of a wind turbine rotor blade, which aerodynamic structure includes a number of comb elements, a comb element including comb teeth arranged in a comb plane, wherein the comb plane of a mounted comb element is essentially perpendicular to the trailing edge of the rotor blade and to the airfoil surface of the rotor blade. A wind turbine rotor blade including at least one such aerodynamic structure, and a method of equipping a wind turbine rotor blade with such an aerodynamic structure, is also provided.