an axial swirler , in particular for premixing of oxidizer and fuel in gas turbines , includes a series of swirl vanes with a streamline cross - section . each swirl vane has a leading edge , a trailing edge , and a suction side and a pressure side extending each between the leading and trailing edges . the swirl vanes are arranged around a swirler axis , wherein the leading edges extend essentially in radial direction . flow slots are formed between the suction side of each swirl vane and the pressure side of its nearest neighboring swirl vane . furthermore , at least one swirl vane has a discharge flow angle between a tangent to its camber line at its trailing edge and the swirler axis that is monotonically increasing with increasing radial distance from the swirler axis . the invention also relates to a burner with such a swirler and a method of operating the burner .