Hydraulic Losses and Flow Patterns of a Swirling Flow in U-Bends

In the past, the hydraulic losses and the flow patterns in pipe bends when a fully developed flow enters the bend were studied. But, practically, most of the flows are not uniform in the axial velocity component and accompanied with a swirling components, which causes different hydraulic losses and flow patterns in the bends. Such problems remain almost unsolved at present. In the present paper, the effects of curvature and surface roughness on the hydraulic losses and flow patterns of a swirling flow in u-bends are studied.