A premixing apparatus for a gas turbine system includes non-swirl elements around a periphery of a face of a premixing apparatus and a swirl assembly located substantially at a center of the face. The non-swirl elements premix a premixture prior to the premixture being delivered to a combustor of the gas turbine system. The swirl assembly disturbs a flow of fluid prior to the fluid being delivered to the combustor. The premixture includes fuel and oxidant, and the fluid disturbed by the swirl assembly includes the oxidant or the premixture.