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. <EOS>