# Drift Potential Characteristics of a Flat Fan Nozzle: A Numerical and Experimental Study
## 2 Model Construction and Numerical Simulation
### Numerical Results
#### 2.3.2 Simulated Droplet Parameters

Table 1: Discrete-phase particle-distribution parameters of simulated nozzles with different inlet wind speeds. Figure 2: Distribution of discrete-phases in space without crosswind. Adjustment and selection exhibited an appropriate discrete-phase-deposition mass-concentration range. As depicted in Figure 4, the droplet horizontal drift increases with an increase in wind speed. As the inlet air velocity increases from 0 m/s to 6 m/s, the droplet horizontal drift becomes more obvious. The high-concentration deposition area gradually deviates from the spray axis (\(x\) = 0 m) and shifts downward in the wind direction. The boundary of the \(x\)-axis area, where the sediment mass concentration is greater than 0.008 kg/m\({}^{3}\), ranges between 5 m and 13 m. Meanwhile, as illustrated in Figure 5, two narrow strips with high sediment concentrations at the junction of the bottom and two walls are observed for the sediment mass concentration of the discrete-phase in the downwind direction. A region of low sediment mass concentration appears at a distance of 0.1 m from the walls on both sides, which gradually elongates along the \(x\)-direction. Figure 4: Distribution of droplets at different wind speeds. Figure 3: Cloud map of discrete-phase deposits concentration on the bottom surface. The airflow streamline graph reveals two parallel X.Y. flows passing through the fan spray surface from the entrance, with a vortex taller than the nozzle. The droplets rise and become smaller on both sides as they move closer to the central plane of the wind tunnel. Meanwhile, the discrete-phase droplet beam has a significant impact on the horizontal airflow, indicating coupling between the droplet and the continuous-phase air and their mutual influence. For the droplets deposited on the bottom, the distribution of deposited mass along the x-axis changes significantly. However, that of the droplets in the \(z\)-axis is nearly symmetrical, forming an M-shape from low to high and then from the central axis down on the z-axis on both sides. Furthermore, the droplet deposition mass in different regions on the inner bottom surface of the wind tunnel was calculated from the result file. The mass in the narrow ellipse was divided by the total discrete-phase deposition mass to obtain an accurate deposition rate at different wind speeds. Meanwhile, the total deposition mass was divided by the droplet deposition mass captured on the ground and air outlet, 2 m behind the downwind direction, to obtain the horizontal drift rate at different wind speeds. The accurate deposition and horizontal drift rates of the discrete-phase under the influence of different lateral wind speeds were obtained (Figure 6). As illustrated in Figure 6, the accurate deposition rate \(R_{a}\) of the simulated discrete-phase decreases exponentially from 14.11% to 0.66% as the lateral wind speed increases  
Figure 5: \(Z\)-direction velocity of discrete-phase particles in the \(Y\) plane is 0.3 m.  
Figure 6: Accurate deposition and horizontal drift rates of simulated discrete-phases under the influence of different crosswinds. from 0 m/s to 6 m/s, and the horizontal drift rate \(R_{h}\) increases linearly from 14.25% to 60.58%. The correlation between these parameters and lateral wind speed was further explored. A regression analysis of the accurate deposition rate, horizontal drift rate, and wind speed was conducted. The correlation equations were \(R_{a}\) = 0.1476 \(\times\) 10\({}^{0.529}\) v (with \(R^{2}\) = 0.995) and \(R_{h}\) = 0.0796 v + 0.1456 (with \(R^{2}\) = 0.995).