Abstract: An insert having a plurality of ports creating angled passageways through the walls of the insert is positioned in a drill string for altering fluid flow in the drill string and inducing vibration sufficient to speed up directional drilling and to prevent differential sticking in wellbores. Boundary layer flow along the walls of the drill string is drawn into an upstream group of ports to commingle with fluid in the central bore of the drill string and the insert. The flow is separated at a downstream group of ports and angled passageways cause the flow to be directed radially outward inducing vibration into the drill string.

Abstract: An anti-reversionary device for installation into the intake or the exhaust of an internal combustion engine comprises an inner pipe substantially centralized in the conduit. A plurality of ports are formed in an annular wall extending between the inner pipe and the conduit. Slower boundary layer gas flow adjacent the conduit is directed through the ports, and accelerated to join the faster gas flow passing through the inner pipe. The annular wall is angled downstream from the inner pipe to the conduit with the ports forming gas flow-directing passages angled radially inwardly. The inner pipe and annular wall are supported in a cylindrical housing forming a unitary body fit to the conduit. One or more devices can be installed in the conduit.