A system includes a gas turbine engine that includes a first combustor and a second combustor. The first combustor includes a first oxidant flow path and a first perforated structure comprising a first plurality of oxidant ports, wherein the first perforated structure is disposed in the first oxidant flow path. The second combustor includes a second oxidant flow path and a second perforated structure comprising a second plurality of oxidant ports. The second perforated structure is disposed in the second oxidant flow path and the first perforated structure has at least one difference relative to the second perforated structure.