An exhaust treatment system includes an exhaust conduit for conveying exhaust gases from an engine of a vehicle. An aftertreatment device is disposed in the exhaust conduit. A flow device is disposed upstream of the aftertreatment device. The flow device includes a base having a first surface and an oppositely disposed second surface. The base defines a plurality of openings. A plurality of flow deflectors is engaged to the base at the plurality of openings. Each flow deflector includes a first deflector that extends outwardly from the first surface of the base and a second deflector that extends outwardly from the second surface of the base. The first and second deflectors define a passage. Flow of exhaust gases through the passage cause exhaust gases to swirl about a longitudinal axis of the exhaust conduit.