Shear-Stress Distribution in Stable Channel Bends

A theoretical and experimental investigation is made concerning the relationships between secondary flow phenomena in alluvial channel bends and boundary shear-stress distribution and related stable bed topography generated in the vicinity of same. The physical model, a wide rectangular channel system in which two-dimensional flow conditions were reproduced, incorporated an adjustable bend test section and bends having central angles of 45—, 60—, and 70? were adopted in the study. Particular emphasis was placed on an examination of the secondary circulation decay process along that portion of the straight channel reach immediately following the bend section. Observed stable bed topography within the bend and along the downstream decay zone related favorably to the steady-state boundary shear-stress distributions obtained from a numerical model of the flow field therein.