Numerical Simulation on Wind-Driven Snow Drift Based on Field Measurements with Dynamic Grids

Wind-driven snow disasters pose severe threats to building structures in cold regions. Existing models lack sufficient accuracy in simulating snow particle transport and dynamic boundary updates (e.g., snowfall-deposition coupling) for complex roof geometries (e.g., double-slope, arch-shaped), limiting their engineering applicability. A multiphysical coupling framework was developed by integrating field measurements and dynamic grid computational fluid dynamics (CFD) simulations. The erosion-deposition model was improved by treating snowfall as a mass source term in the Navier–Stokes equations, with the Realizable k‒ε turbulence model resolving turbulent flow around roofs. Key findings include: (1) vortex structures on double-slope roofs induce local snow erosion (windward) and accumulation (leeward), with maximum snow load reaching 2.3 times the initial snowfall; and (2) arch-shaped roofs enhance snow transport via curvature-induced circulation, leading to more uniform but higher peak loads (15% greater than double-slope roofs). Dynamic grids accurately captured time-varying snow boundaries (grid update error <5%), validating the model’s capability for snow-load prediction. Temperature-induced snow compaction (phase change) and irregular snow particle shapes (affecting settling velocity, <10% error) were not modeled, requiring future integration of thermodynamic and discrete-element methods.