A fuel nozzle assembly includes a swirler assembly having an inlet end, an outlet end, a shroud inner surface and a hub outer surface. The inner surface has a first diameter adjacent to the inlet end and a second diameter adjacent to the outlet end defining a differential diameter ratio. A plurality of vanes are coupled to the swirler assembly and extend between the shroud inner surface and the hub outer surface. The vanes have a pair of opposing sidewalls joined at a leading edge and at an axially-spaced trailing edge, and a first height adjacent to the leading edge and a second height adjacent to the trailing edge. The first height and the second height define a differential height ratio, wherein the differential diameter ratio, the differential height ratio, or both are configured to provide convergent flow through the fuel nozzle.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH & DEVELOPMENT
 This invention was made with Government support under DE-FC26-05NT42643 awarded by the Department of Energy ("DOE"). The Government has certain rights in this invention.