PSI - Issue 73

Ivan Kolos et al. / Procedia Structural Integrity 73 (2025) 58–65 Author name / Structural Integrity Procedia 00 (2025) 000 – 000

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Table 2. Variant +X | – Z60: droplets in kg in sampling planes at distances of 5, 9 and 13 m from the road axis. Amount of droplets [kg] Sampling plane 5 Sampling plane 9 Sampling plane 13 Part 1 0.054 0.286 0.265 Part 2 0.714 0.041 0 Part 3 0.779 0.575 0.535 Part 4 0.147 0.162 0.187

Fig. 6 shows the aerosol wake behind running vehicles for both analysed wind directions. The figures clearly show the difference in aerosol dispersion for both cases. While for variant +X | +Z60, a large number of droplets stayed close to the road, in the second variant, the droplets were sprayed at a much greater distance from the road.

Fig. 6. Aerosol wake behind running vehicles. Left: +X | +Z60, right: +X | – Z60.

4. Conclusion The results of the simulations show that the wind has a significant influence on the amount of aerosol that reaches the distances at which the monitoring planes are defined. The notch in the terrain, in which the road with both vehicles is located and which defines the shape of the computational domain being solved, supports turbulent flow. Vortices rotating around axes parallel to the X axis dominate this turbulent flow in terms of aerosol dispersion. This results in the particle cloud being deflected from the sampling planes or, conversely, the particle cloud being guided to the sampling planes. The direction and range of the aerosol is then additionally supported by the 25° inclination of the end wall of the domain to the horizontal plane. This allows the particles to hit the sampling planes even relatively high above the level of the wheels of the vehicles from which the particles are released. The real range of aerosol particles may differ significantly from the created computational model, which is idealised in many respects, especially due to the necessary neglect of the difficult-to-model coarseness of free-growing vegetation near the road. The resulting values in this paper correspond to the passage of the two cars and the given wind directions. This research can be followed up in further numerical studies and provide an idea of aerosol dispersion in the vicinity of the road for different traffic situations, wind directions, and velocities, and thus obtain a comparison with real in situ measurements.