Experimental Study of Secondary Flow in Narrow and Sharp Open-Channel Bends

Secondary flow is a prominent feature of channel bends; it alters the streamwise velocity and bed shear stress distributions. Experiments were conducted to investigate complex pattern secondary in narrow sharp open-channel bend underlying mechanism generation multiple circulation cells. Compared with moderate bends, bends are characteristic cells from 90° section. In addition curvature-induced cell (S1) turbulence-induced counter-rotation (C1) near outer bank, another (S2) was observed inner bank attributed separation. A term-by-term analysis vorticity equations indicates that centrifugal term favours S1 C1 while opposing S2. The turbulence-related accounts for formation advective transport redistributes maintains existence dependence structure on Reynolds number aspect ratio also explored. With an increase 23000 37000, both strength size reduced by 50%, whereas S2 increases 20%, its slightly decreases. decrease 3.3 2, strengths S1, S2, doubled, sizes 90% respectively.