This technical note presents the DualSPHysics application to spillway hydraulics, and an extensive comparison has been made between the single-water and two-phase water–air modelling approaches. It has been found that the DualSPHysics code based on the smoothed particle hydrodynamics method could provide a promising design tool for spillway flows in the engineering field. The model is first validated on a documented skimming flow and the numerical results are also compared with those computed from a smoothed spillway flow. Then the model is further validated by a laboratory experiment for a nappe flow, where the computed flow depth and velocity are validated against the physical measurements. It has been disclosed that for a skimming flow, the single- and two-phase SPH modelling approaches lead to small differences, while for a nappe flow with more serious free surface motion, the two-phase model clearly improved the simulation accuracy. After the model is fully validated, it is applied to investigate a practical spillway flow under different flow discharges, bed slopes and step numbers, covering two distinct spillway flow regimes. From the simulation results, the flow energy dissipation features are investigated with regards to the different flow rates and spillway configurations. It has been found that the energy dissipation efficiency of a spillway is proportional to the number of the steps but inversely proportional to the flow discharge and the spillway slope.

In this study, a three-dimensional (3D) numerical model based on the smoothed particle hydrodynamics (SPH) approach was developed to simulate the near-shore current flows over a rough topographic surface in the coastal area, where the flows are shallow and demonstrate strong turbulent characteristics. The numerical program is based on the open-source code SPHysics (http://www.sphysics.org), and two major improvements are made to treat the turbulence and rough boundary effects: A modified sub-particle-scale (SPS) eddy viscosity model is developed to address the turbulence transfer of flows, and a drag force equation is included in the momentum equations to account for the influence of roughness element on the bed and lateral boundaries. The computed results of flow velocity, shear stress, and free surface characteristics are compared with the laboratory measurements for a variety of test conditions. It has shown that the present SPH model can accurately simulate 3D-free surface near-shore current flows over a realistic topography with roughness.

Long-distance water conveyance channels are vital for optimizing water resource allocation in China, yet ice-cover damage induced by thermal stress during temperature fluctuations poses significant risks to structural stability. To address this challenge, we develop a mesh-free thermal conduction and stress model based on the smoothed particle hydrodynamics (SPH) method, enabling high-fidelity simulations of ice-cover behavior in rectangular and trapezoidal channels. By analyzing temperature and stress distributions under varying ice thickness, initial surface temperatures, and temperature rise rates, research results demonstrate that ice thickness and initial temperature govern peak thermal stress magnitude while warming rates determine stress duration. Crucially, trapezoidal channels exhibit 9.19% lower average thermal stress compared to rectangular sections, attributable to their geometric stress-dispersing properties. These findings advocate trapezoidal cross sections as a safer design choice for cold-region water conveyance systems and underscore the need for protective measures during slow-warming phases. This work establishes SPH as a novel, grid-independent framework for ice-engineering analyses, overcoming the limitations of traditional mesh-based approaches in simulating complex thermomechanical interactions.