The Nature of Flow in an Elbow

The available information on fluid flow diversion is limited largely to the experimental value 6 of the bend loss coefficient, and the variation of this coefficient with such factors as radius ratio, aspect ratio, and deflection angle. Some analytical work has also been done in the laminar flow region and on two-dimensional bends of continued curvature. There has been a decided need, however, for a general theory explaining the flow phenomenon and the mechanism of energy loss in a three-dimensional bend of fixed deflection angle. This report describes experiments which were directed toward obtaining such information.