A flow control device for an additive manufacturing system, the additive manufacturing system defining a first, longitudinal direction, a second, horizontal direction, and a third, vertical direction], the three directions being orthogonal to each other, said flow control device comprising: a gas supply configured to discharge a gas, wherein said gas supply device comprises a first gas supply and a second gas supply, wherein said first gas supply is configured to discharge a first portion of a gas along the first direction, substantially parallel to a build layer and wherein said second gas supply is configured to discharge a second portion of a gas along the third direction which is orthogonal to the first direction and substantially perpendicular to the build layer; a first flow modifier configured to modify at least one flow characteristic of the first portion of the gas; and a second flow modifier configured to cooperate with the first flow modifier to modify the at least one flow characteristic of the first portion of the gas, wherein said second flow modifier is further configured to modify at least one flow characteristic of the second portion of the gas, and wherein said first flow modifier and said second flow modifier are configured to cooperate to direct at least a portion of the first portion and the second portion of the gas towards a melt pool in a build layer; wherein said first flow modifier comprises a first flow feature extending along the second direction, and wherein said second flow modifier comprises at least one second flow feature extending along the second direction; and wherein each of said first flow feature and said second flow feature is at least one of an airfoil shape, a spherical shape, a ramp shape, a nozzle shape, and a hyperbolic shape. a gas supply configured to discharge a gas, wherein said gas supply device comprises a first gas supply and a second gas supply, wherein said first gas supply is configured to discharge a first portion of a gas along the first direction, substantially parallel to a build layer and wherein said second gas supply is configured to discharge a second portion of a gas along the third direction which is orthogonal to the first direction and substantially perpendicular to the build layer; a first flow modifier configured to modify at least one flow characteristic of the first portion of the gas; and a second flow modifier configured to cooperate with the first flow modifier to modify the at least one flow characteristic of the first portion of the gas, wherein said second flow modifier is further configured to modify at least one flow characteristic of the second portion of the gas, and wherein said first flow modifier and said second flow modifier are configured to cooperate to direct at least a portion of the first portion and the second portion of the gas towards a melt pool in a build layer; wherein said first flow modifier comprises a first flow feature extending along the second direction, and wherein said second flow modifier comprises at least one second flow feature extending along the second direction; and wherein each of said first flow feature and said second flow feature is at least one of an airfoil shape, a spherical shape, a ramp shape, a nozzle shape, and a hyperbolic shape.