Planform evolution of a sinuous channel triggered by curvature and autogenic width oscillations due to generic grain transport

Abstract

We study the dynamics of an erodible sinuous channel subject to combined curvature and autogenic width oscillations. We find that generic grain transport (both bedload and suspended load transport) amplifies lateral stretching of the channel centerline and enhances the maximum width-variation amplitude and curvature ratio in their temporal dynamics by displaying a phase lag. However, in the initial and mature stages, the planform dynamics asymptotically approaches the conventional limits. The planform evolution is found to be influenced by four key parameters: Shields number, relative roughness, channel aspect ratio, and shear Reynolds number. The findings of this study, to the best of our knowledge, represent the first analytical investigation of the planform evolution of a sinuous channel driven by generic grain transport.