Mechanisms Controlling Dust Aerosol Collection by Isolated Obstacles Near the Ground

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Abstract The collection of dust aerosols (0.1–10 m) by near‐surface obstacles is one of the important processes in atmospheric aerosol dry deposition. However, existing understanding of this process remains limited. For example, most current deposition models assume complete deposition or describe the collection process through empirical models, making it difficult to accurately predict the concentration distribution of dust particles within the near‐surface collection layer. In this study, the effects of turbulence around obstacles are considered to improve an existing numerical model for simulating aerosol particle deposition in rough surface environments. The modified numerical model is validated through wind tunnel experiments. Subsequently, the particle collection process on an isolated cylindrical obstacle placed on the ground is investigated using numerical simulations. The effects of different wind conditions, particle properties, and obstacle sizes on the collection process are analyzed. Finally, a fitted relationship between the Stokes number and collection efficiency is proposed. The results show that inertial impaction and interception jointly dominate particle deposition on the windward side of the isolated obstacle, while turbulence‐induced impaction governs deposition on the leeward side. Therefore, parameters that affect particle inertia and the turbulent flow around the obstacle have a more significant impact on the particle deposition process. The simulation results agree well with existing experimental data and exhibit lower data dispersion, demonstrating that the numerical model developed in this study can effectively describe the collection of particles by near‐surface obstacles. This provides a solid basis for improving atmospheric particle deposition models.

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