# Numerical Simulation Research on Plane Alignment Parameters of Desert Highway
## 3 Results and Analysis  
### Analysis of the Results of the Angle Embankment Model  
#### 3.1.1 Distribution Characteristics of the Wind-Sand Flow Field  
Taking the sand-carrying wind of 18 m/s as the inlet velocity of the flow field, the wind-sand movement law of the straight embankment under different angles conditions (\(\alpha\) = 90\({}^{\circ}\), 50\({}^{\circ}\), 30\({}^{\circ}\)) is simulated, and the cross-section at the middle position of the flow field (Y = 30 m) is taken to compare the flow-field structure changes around the embankment. It can be seen from Figure 3 that, when the wind-sand flow passes through the embankment, the speed is divided into zones. The wind-sand flow forms a deceleration zone, an acceleration zone, a high-speed zone, and a low-speed zone at the windward side of the slope toe, slope surface, road shoulder, road center, and the leeward side of the slope foot, respectively. However, under the action of different angles, the structure of the wind-sand flow field around the embankment is different. When the angle \(\alpha\) is 90\({}^{\circ}\), the wind-sand flow can form an obvious deceleration and acceleration area at the toe of the embankment. When \(\alpha\) is reduced to 30\({}^{\circ}\), the deceleration area on the windward side of the embankment and the vortex area on the leeward side of the embankment are significantly reduced, the changes of each wind speed block are difficult to distinguish, and the transition of the wind-sand flow passing through the embankment is gentle. It can be seen that, under the condition of constant wind speed, the degree of speed change around the embankment decreases with the decrease in the angle \(\alpha\) between the wind direction and the line direction, and the speed-zone range of the wind-sand flow when passing the embankment is also reduced. The reason for this is that the change of the incoming wind direction changes the slope and the width of the road embankment. When the angle \(\alpha\) is 90\({}^{\circ}\), the cross-section of the embankment passing by the wind-sand flow is 38 m wide, the grade of the side slope is 1:3, the embankment has a great hindering effect on the wind-sand flow, and the flow-field division of the embankment cross-section is obvious. When the angle \(\alpha\) is 30\({}^{\circ}\), the cross-section of the embankment passing by the  
Figure 2: Comparison of wind-speed profiles between wind-tunnel test and numerical simulation. wind-sand flow is 76 m wide, and the grade of the side slope is 1:6. The increase in the pavement width and the decrease in the grade of the side slope reduces the energy loss of the wind-sand flow when passing through the embankment, the speed change is gentle, and the zoning phenomenon is not obvious. In order to further study the law of wind-blown sand movement at different positions along the line, when the angle \(\alpha\) is 50\({}^{\circ}\), flow-field analysis is carried out on the cross-section of the embankment at different positions (Y = 10 m, Y = 30 m, Y = 50 m), and the results are shown in Figure 4. It can be seen that there are obvious differences in the flow-field distribution of the three embankment cross-sections. The variation of airflow around the embankment under oblique wind conditions is different from the symmetrical flow-field structure under orthogonal wind conditions. The flow-field distribution changes with the position of the road, especially at the shoulder of the road: when Y = 10 m, the airflow on the upper shoulder of the windward slope is relatively dispersed, and when Y = 50 m, the airflow on the upper shoulder of the windward slope is gradually tight. The reason for this is that when the oblique wind-sand flow passes through the embankment, the wind-sand flow at the starting point of the line first crosses the embankment.