Abstract The interaction between the asymmetric vortex pair and the ground was experimentally investigated in a closed-circuit water channel for the current study. Particle image velocimetry tests were conducted to achieve the velocity measurements of flow fields at various crossflow planes. The vortex pair, with the reference circulation Reynolds number Re Γ ≈ 4490, was tested with various initial heights ( h 0 / b 0 = 1.5, 1.0 and 0.5) and circulation ratios ( λ = 0.36:1, 1:0.36, 0.6:1, 1:0.6), with it being found that according to different interaction effects, the trajectory and merger of the vortex pair could be significantly affected. As the primary vortex pair approached the ground, a high turbulent kinetic energy region was observed between the secondary and primary vortical structures, which suggests violent interaction and accelerated circulation decay of the primary vortex. In addition, depending on the distribution of secondary vorticity and image vortices to the moving coordinate system, merging-promoting or -inhibiting effects were observed, which eventually affected the evolution of the primary vortex pair. Graphic abstract

中文翻译：

---

非对称涡对与地面相互作用的实验

摘要 本研究在闭路水道中对非对称涡对与地面的相互作用进行了实验研究。进行粒子图像测速测试以实现各种横流平面流场的速度测量。参考循环雷诺数 Re Γ ≈ 4490 的涡流对在不同的初始高度（h 0 / b 0 = 1.5、1.0 和 0.5）和循环比（λ = 0.36:1、1:0.36、0.6: 1, 1:0.6)，发现根据不同的相互作用效应，涡对的轨迹和合并会受到显着影响。当初级涡对接近地面时，在次级和初级涡结构之间观察到一个高湍动能区，这表明主涡旋的剧烈相互作用和加速的循环衰减。此外，根据次生涡量和图像涡在运动坐标系中的分布，观察到了合并促进或抑制效应，最终影响了初级涡对的演化。图形摘要