Protective barrier systems are widely used to reduce the impacts of water floods and viscoplastic debris flows. Our previous work Kefayati et al., “The effect of porosity in a row of barriers on mitigation of flow dynamics and barrier interaction: Water floods and viscoplastic debris flows in a complex terrain,” Phys. Fluids 37, 123112 (2025) examined the influence of barrier porosity in a complex terrain catchment in Hobart, Tasmania; however, the effects of different barrier sizes, numbers, and void distributions while maintaining a fixed porosity on force transmission and flow attenuation remain insufficiently understood. This study conducts high-resolution three-dimensional computational fluid dynamics (CFD) simulations to quantify the maximum forces acting on barrier arrays and on the downstream end wall for a set of configurations with a constant porosity ϕ=0.4. Fourteen arrangements, differing in barrier count and spatial layout, are evaluated under both flood and debris-flow conditions. For water floods, the results show that the first barrier consistently sustains the largest forces, with peak loads of up to 9.6×105 N. Increasing the number of barriers yields only moderate reductions in these forces, and the forces on the end wall remain nearly unchanged across all cases, ranging between 3.1 and 3.6×105 N. In contrast, viscoplastic debris flows display a strong sensitivity to the number and arrangement of barriers. As n increases, the barrier experiencing the maximum load shifts progressively downstream (e.g., from B1 to B6), driven by material accumulation, yield-stress effects, and internal stress redistribution. End-wall forces decrease substantially with larger arrays, reducing from 14.43×104 N in sparse configurations to below 2×104 N when twelve barriers are used, indicating a significant improvement in flow attenuation.
Kefayati et al. (Thu,) studied this question.