A burner includes a cylindrical tube that terminates in a burner discharge end. An annular disk, affixed to the discharge end, defines a hole. An oxidizer intake delivers oxidizer into the tube. A fuel nozzle delivers fuel into the tube. A cylindrical slotted member has an interrupted outer surface and is disposed within a portion of the tube. The slotted member is affixed to the annular disk and defines an interior void that opens to the hole. The tube and the slotted member define an annular passage therebetween. Elongated slots pass through the outer surface of the slotted member, each directed along a different non-diametrical chord of the slotted member. The elongated slots direct a gaseous stream into the interior void so as to impart both an inwardly-directed radial velocity component and a tangential velocity component to the gaseous stream.