An improved air entrainment model for stepped spillways

Journal article, 2021

This work considers the application of the air entrainment model developed in [P. Lopes et al. Int. J. Nonlin. Sci. Num., vol. 18, pp. 559-574, 2017] to simulation of flows in stepped spillways. Four Froude numbers are considered for the flow, with parameters selected to match available experimental data. An extensive simulation campaign led to the identification of several deficiencies in the model, most importantly, its strong grid dependence. An improvement to the interface detection algorithm used in the model is proposed, and simulations reveal improved robustness with respect to the grid density. Furthermore, two criteria for predicting the inception point of air entrainment are tested, based on energy balance and boundary layer state, respectively. The boundary layer-based approach is recommended due to superior accuracy and robustness with respect to turbulence model selection.