PSI - Issue 63

Ivan Kolos et al. / Procedia Structural Integrity 63 (2024) 13–20

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This road cut is used for the creation of the domain in the ANSYS Fluent 2023 R2 software for a model of a moving truck of which the flow field is solved.

3. Numerical analysis 3.1. Numerical model

Dimensions of the domain are based on the real geometry of the nearby road, on which probes are installed to measure the amount of chloride deposits. The computing domain is 240 m long, 60 m wide and 15.85 m high and it is divided into 3 zones (Fig. 2): preparation zone (120 m long), analytic zone (90 m long), exit zone (30 m long).

Fig. 2. Computational domain divided into zones.

The truck was placed in a separate subdomain in a 410 m long box, which allows simulation of the movement of the vehicle using the sliding mesh technique. The vehicle was located at a distance of 60 m from the analytical domain. This distance is assumed to be sufficient for the flow around the vehicle to fully develop before entering the analytic zone. The domain mesh consists of 800 thousand polyhedral cells. Cells in close vicinity of vehicle have diameter within range 0.05 and 0.2 m, maximum size of all other cells is 0.5 m. The vehicle was modeled in a simplified geometry based on Ardian (2018). It represents a general, most commonly used, truck with a length of 16 m, a width of 2.7 m and a height of 4 m. Preliminary study calculations have shown that the detailed modelling of droplet spraying by the entry of a rotating wheel into the liquid layer is inefficient due to the scale of the task, with excessively high demands on computing power. Therefore, a simplifying model was considered, where particles are injected from sidewalls of tires. Inert particles of constant diameter 2.5e-5 m, total flow rate 4.5 kg/s (based on Lottes and Bojanowski (2013)), initial particles velocity magnitude is 25 m/s, material of particles is simplified to liquid water with density 998.2 kg/m 3 . Total run time of the vehicle is 7.2 s. After 2.4 s, the vehicle enters the analytic zone and after 4.8 s reaches end face of the exit zone. Particles are evenly injected from the vehicle's wheels throughout the entire travel. Four directions of the wind are simulated in the model, two from the front and two from the back, all with the wind entering at 60-degree angle. Wind direction is shown schematically in Fig. 3. The angle is measured in the xz plane relative to the x-axis. The directional vector of the wind is horizontal, i.e. it lies in the xz plane.