Similitude-scaled criterion for investigating the snow and ice accumulation in the bogie regions of high-speed train

Abstract

Full-scale wind tunnel experiments investigating snow and ice accumulation in the bogie regions of high-speed trains are both expensive and technically demanding due to equipment constraints. Although scaling methods provide a more economical alternative, a well-established theoretical framework for simulating snow and ice particle dynamics in this context remains absent. This study proposes a snow particle scaling criterion based on aerodynamic similarity. Specifically, when the ratio of the product of particle density and diameter before and after scaling aligns with the model's geometric scaling ratio, their transport and deposition behaviors remain consistent. The proposed criterion was verified through numerical simulations by comparing three scaling strategies against the full-scale baseline case. The accuracy of the numerical method was further validated against both single-phase wind tunnel experiments and full-scale snow and ice wind tunnel tests. Results indicate that scaling only the particle density most effectively preserves the snow partial motion and accretion distribution characteristics. When only the particle diameter is scaled, the particle mass decreases most significantly, which markedly alters the particle's motion trajectories. Compared to the baseline case, average changes in particle accretion thickness were 0.8%, 29.8%, and 10.0% for the bogie gearbox, and 0.8%, 28.9%, and 10.1% for the motor under density-only, diameter-only, and combined scaling, respectively. These findings suggest that maintaining the original particle diameter while scaling only the density most accurately preserves snow accumulation behavior, thereby supporting experimental investigations of snow and ice phenomena in the bogie regions of high-speed trains.