Abstract: A device for reducing friction of a viscous fluid flow in a conduit is disclosed. The device comprises a body positionable to define at least a segment of a flow path for the viscous fluid in or contiguous with the conduit, a cavity in the body for retaining lubricating fluid, and at least one port in the body for delivering lubricating fluid to the cavity. A fluid outlet arrangement from said cavity delivers lubricating fluid to the flow path to form a downstream lubricating film at the conduit surface. The fluid outlet arrangement comprises a substantially continuous opening or ring of close spaced openings, effective collectively to reduce the pressure variation and therefore velocity variation of the delivered lubricating fluid along said outlet arrangement.

Abstract: A device for reducing friction of a viscous fluid flow in a conduit includes a body (10,110) positionable to define at least a segment of a flow path for the viscous fluid in or contiguous with the conduit, a cavity (40,140) in the body for retaining lubricating fluid, and at least one port (42,142) in the body for delivering lubricating fluid to the cavity. A fluid outlet arrangement (48,148) from the cavity delivers lubricating fluid to the flow path to form a downstream lubricating film about viscous fluid flowing therein. The fluid outlet arrangement comprises a substantially continuous opening or ring of close spaced openings about the flow path. The cavity comprises an array of passages in the body that includes a plurality of elongate passages (55,155) that extend about the flow path effective collectively to reduce the pressure variation and therefore velocity variation of the delivered lubricating fluid along the outlet arrangement. A corresponding method is also disclosed.