Mechanism to reduce turning losses in conduits

A loss reducing insert adapted to overlie and replace the inner corner flow surface of the internal surface of a turn in a fluid flow duct, said insert comprising an upstream end, a downstream end and means to generate large scale vortices and produce a flow variation which disrupts the eddy flow in the separation region to reduce turning losses, said means including a plurality of downstream extending, adjoining alternating troughs and ridges, extending from said upstream end of said flow insert to said downstream end of said flow insert, said ridges increasing in height from said upstream end to a maximum height downstream and decreasing in height from said maximum height to zero height at said downstream end, said plurality of troughs and ridges defining a convoluted surface.