A fuel injector configured to be disposed in a combustor of a gas turbine engine, said combustor comprising: an end cover ; at least one fuel nozzle extending between the end cover and a combustion liner , wherein the combustion liner extends between the at least one fuel nozzle and an aft frame and defines a combustion chamber; said fuel injector configured to be disposed downstream from the at least one fuel nozzle and in fluid communication with the combustion chamber, said fuel injector comprising a forward end wall and an aft end wall disposed opposite from the forward end wall ; side walls extending between the forward end wall and the aft end wall , wherein the forward end wall , the aft end wall , and the side walls collectively define an opening for passage of air; at least one fuel injection member disposed within the opening and extending between the end walls ; and a fuel circuit defined within the fuel injector , the fuel circuit comprising: an inlet plenum defined within the forward end wall of the fuel injector ; and a fuel passage extending from and in fluid communication with the inlet plenum , the fuel passage defined within the at least one fuel injection member , characterized in that the fuel passage has a cross-sectional area that varies along a length of the fuel injection member ; wherein the fuel passage includes a first converging portion , a diverging portion , and a second converging portion . an end cover ; at least one fuel nozzle extending between the end cover and a combustion liner , wherein the combustion liner extends between the at least one fuel nozzle and an aft frame and defines a combustion chamber; said fuel injector configured to be disposed downstream from the at least one fuel nozzle and in fluid communication with the combustion chamber, said fuel injector comprising a forward end wall and an aft end wall disposed opposite from the forward end wall ; side walls extending between the forward end wall and the aft end wall , wherein the forward end wall , the aft end wall , and the side walls collectively define an opening for passage of air; at least one fuel injection member disposed within the opening and extending between the end walls ; and a fuel circuit defined within the fuel injector , the fuel circuit comprising: an inlet plenum defined within the forward end wall of the fuel injector ; and a fuel passage extending from and in fluid communication with the inlet plenum , the fuel passage defined within the at least one fuel injection member , characterized in that the fuel passage has a cross-sectional area that varies along a length of the fuel injection member ; wherein the fuel passage includes a first converging portion , a diverging portion , and a second converging portion . an inlet plenum defined within the forward end wall of the fuel injector ; and a fuel passage extending from and in fluid communication with the inlet plenum , the fuel passage defined within the at least one fuel injection member , characterized in that the fuel passage has a cross-sectional area that varies along a length of the fuel injection member ; wherein the fuel passage includes a first converging portion , a diverging portion , and a second converging portion . <EOS>