Effect of Froude similitude deviation on curved channel simulations: A case study in the Middle Yangtze River

Froude similitude and friction similitude are the two crucial similarity conditions that are often used in physical-scale modeling of rivers. However, models often deviate from Froude similitude when dealing with real-world situations. This study developed several fixed-bed river models with various curvatures to determine the effect of Froude similitude deviation on curved channel modeling. Models were constructed according to the characteristics of the Middle Yangtze River. Differences in longitudinal slope, transverse slope, and main stream line location were measured by varying Froude similitude deviation. The deviations of longitudinal slope and velocity were negligible because friction similitude was accounted for. The transverse slope varied significantly with the Froude similitude deviation, and the main stream line varied with the curvature and Froude similitude deviation. Formulae were derived to estimate the slope deviation. These analyses helped to clarify the feasibility of the method of Froude similitude deviation for curved channels.