Characteristics of turbulent flow over a steep escarpment were studied using a 1:25 scale model of the Bolund hill in a wind tunnel under neutral atmospheric stability conditions. The influence of Reynolds number, inflow shear profile, and escarpment geometry were investigated in relation to flow behavior including separation and reattachment, Reynolds stresses, vorticity, Turbulent Kinetic Energy (TKE) production, and Gaussianity. Multi-camera Particle Image Velocimetry (PIV) was used to examine the flow in the vicinity of the escarpment leading edge. Four test cases were studied across a Reynolds number range of $1\times {10}^5<R{e}_h<5\times {10}^5$. Two different inflow profiles were evaluated, as well as two different leading edge geometries – a round edge with non-dimensional radius of curvature a$\eta \approx 0.2$ and a sharp edge with $\eta \approx 0$. A sharp leading edge was found to produce a well-defined separation bubble, yielding distributions and magnitudes of Reynolds stress, vorticity and TKE production closely resembling those of flow over an idealized forward facing step, as well as full-scale measurements of TKE. Gaussianity of the flow was significantly modified by the escarpment, with high skewness and kurtosis occurring in the sharp edge case along the boundary of the separation bubble.

在中性大气稳定条件下，使用风洞中Bolund丘陵的1:25比例模型研究了陡峭悬崖上的湍流特征。研究了雷诺数，流入剪切剖面和陡峭几何形状对与流动行为（包括分离和重新附着，雷诺应力，涡度，湍动能（TKE）产生和高斯性）有关的影响。多摄像机粒子图像测速（PIV）用于检查悬崖前缘附近的流量。在雷诺数范围内研究了四个测试用例$\mathrm{1个}\times {10}^5<\mathrm{[R}{Ë}_H<5\times {10}^5$。评估了两种不同的流入剖面，以及两种不同的前缘几何形状–具有无量纲曲率半径a的圆形边缘$\eta \approx 0.2$ 和一个锋利的边缘 $\eta \approx 0$。发现尖锐的前缘会产生清晰的分离气泡，产生雷诺应力，涡度和TKE产生的分布和大小，与理想化的前向台阶上的流量以及TKE的满量程测量非常相似。陡峭地改变了流动的高斯性，沿着分离气泡的边界在锋利的边缘情况下发生了高的偏度和峰度。