Slope variation will significantly affect the characteristics of the wind field around a hill. This paper conducts a large-eddy simulation (LES) on an ideal 3D hill to study the impact of slope on wind field properties. Eight slopes ranging from 10° to 45° at 5° intervals are considered, which covers most conventional hill slopes. The inflow turbulence for the LES is generated by adopting a modified generation method that combines the equilibrium boundary conditions with the Fluent inherent vortex method to improve the simulation accuracy. The time-averaged flow field and the instantaneous vortex structure under the eight slopes are comparatively analyzed. The accuracy of the present method is verified by comparison with experimental data. The slope can affect both the mean and fluctuating wind flow fields around the 3D hill, especially on the hilltop and the leeward side, where a critical slope of 25° can be observed. The fluctuating wind speeds at the tops of steep hills (with slope angles beyond 25°) decrease with increasing slope, while the opposite phenomenon occurs on gentle hills. With increasing slope, the energy of the high-speed descending airflow is enhanced and pushes the separated flow closer to the hill surface, resulting in increased wind speed near the wall boundary on the leeward side and inhibiting the development of turbulence. The vortex shedding trajectory in the wake region becomes wider and longer, suppressing the growth of the mean wind near the wall boundary and enhancing the turbulence intensity.

坡度变化将显着影响山丘周围风场的特征。本文对理想的 3D 山丘进行大涡模拟 (LES)，以研究坡度对风场特性的影响。考虑了 8 个坡度，范围从 10° 到 45°，间隔 5°，涵盖了大多数常规山坡。LES的入流湍流采用改进的生成方法生成，将平衡边界条件与Fluent固有涡法相结合，提高了模拟精度。对8个坡度下的时均流场和瞬时涡结构进行了对比分析。通过与实验数据的比较验证了该方法的准确性。坡度会影响 3D 山周围的平均风流场和脉动风流场，尤其是在山顶和背风面，可以观察到25°的临界坡度。陡峭山坡（坡角超过25°）顶部的脉动风速随着坡度的增大而减小，而平缓山坡则出现相反的现象。随着坡度的增大，高速下降气流的能量增强，将分离流推向山面，导致背风面墙边界附近的风速增大，抑制湍流的发展。尾流区涡脱落轨迹变宽变长，抑制了壁面边界附近平均风的增长，增强了湍流强度。陡峭山坡（坡角超过25°）顶部的脉动风速随着坡度的增大而减小，而平缓山坡则出现相反的现象。随着坡度的增大，高速下降气流的能量增强，将分离流推向山面，导致背风面墙边界附近的风速增大，抑制湍流的发展。尾流区涡脱落轨迹变宽变长，抑制了壁面边界附近平均风的增长，增强了湍流强度。陡峭山坡（坡角超过25°）顶部的脉动风速随着坡度的增大而减小，而平缓山坡则出现相反的现象。随着坡度的增大，高速下降气流的能量增强，将分离流推向山面，导致背风面墙边界附近的风速增大，抑制湍流的发展。尾流区涡脱落轨迹变宽变长，抑制了壁面边界附近平均风的增长，增强了湍流强度。导致背风侧壁边界附近的风速增大，抑制湍流的发展。尾流区涡脱落轨迹变宽变长，抑制了壁面边界附近平均风的增长，增强了湍流强度。导致背风侧壁边界附近的风速增大，抑制湍流的发展。尾流区涡脱落轨迹变宽变长，抑制了壁面边界附近平均风的增长，增强了湍流强度。