The control of the unsteady flow structure formed behind a cylinder placed horizontally in shallow water was analyzed experimentally using bare cylinder and cylinders with cavities having square and rectangular geometries, respectively. Reynolds number, Froude number and water height had been chosen as 5000, 0.27 and 90 mm, respectively and also these parameters were kept constant for all experiments. To consider the influence of height (h), the cylinder level was located at various heights from h: 0 mm to 60 mm. Furthermore, cavity angle (a) had been selected from 0°, 80°, 85°, 90° and 95° to consider influence of cavity angle on flow. With the help of Particle Image Velocimetry (PIV), average velocity vectors were measured in two dimensions at many points simultaneously in a planar flow area. The results uncovered that large negative counter was observed at h: 37.5 mm in bare cylinder as well as cylinders having square and rectangular cavities at h: 45 mm. Also, no negative counter was observed for cylinders having rectangular cavity at h: 0 mm and a: 90° and 95° due to the bottom effect. Due to surface effects, a foci point was formed in all cylinders where close to the surface and close to the base. Two foci points and a saddle point were seen as they moved away from the surface for all cylinders. Also, the smallest vortex region was observed for cylinders having rectangular cavity at h: 37.5 mm and a: 90° and 95° in whole cylinders. Also, the highest drag coefficient (C_d) value was obtained for cylinder having square cavity at h: 52.5 mm and a: 80° while the highest drag coefficient value was obtained for cylinder having rectangular cavity at h: 37.5 mm and a: 95°.

使用裸缸和具有分别具有正方形和矩形几何形状的空腔的缸，通过实验分析了在水平放置在浅水中的缸后面形成的非定常流动结构的控制。雷诺数，弗洛德数和水高分别选择为5000、0.27和90 mm，并且在所有实验中这些参数保持恒定。为了考虑高度（h）的影响，圆柱体高度位于h：0 mm至60 mm的各种高度。此外，考虑到腔角对流动的影响，从0°，80°，85°，90°和95°中选择腔角（a）。借助粒子图像测速（PIV），可以在平面流动区域中的多个点同时在二维上测量平均速度矢量。结果发现，在裸圆柱体以及在h：45mm处具有正方形和矩形腔的圆柱体中，在h：37.5mm处观察到大的负计数器。另外，由于底部效应，对于在h：0mm和a：90°和95°处具有矩形腔的圆柱体，未观察到负计数器。由于表面效应，在所有靠近表面且靠近底部的圆柱体中都形成了焦点。当它们移离所有圆柱体的表面时，可以看到两个焦点点和一个鞍点。同样，在整个圆柱体中，对于具有矩形腔的圆柱体，在h：37.5 mm且a：90°和95°处观察到最小的涡旋区域。另外，最高阻力系数（C 由于底部效应，对于在h：0 mm和a：90°和95°处具有矩形腔的圆柱体，未观察到负计数器。由于表面效应，在所有靠近表面且靠近底部的圆柱体中都形成了焦点。当它们移离所有圆柱体的表面时，可以看到两个焦点点和一个鞍点。同样，在整个圆柱体中，对于具有矩形腔的圆柱体，在h：37.5 mm且a：90°和95°处观察到最小的涡旋区域。另外，最高阻力系数（C 由于底部效应，对于在h：0 mm和a：90°和95°处具有矩形腔的圆柱体，未观察到负计数器。由于表面效应，在所有靠近表面且靠近底部的圆柱体中都形成了焦点。当它们移离所有圆柱体的表面时，可以看到两个焦点点和一个鞍点。同样，在整个圆柱体中，对于具有矩形腔的圆柱体，在h：37.5 mm且a：90°和95°处观察到最小的涡旋区域。另外，最高阻力系数（C 在整个圆柱体中，对于在h：37.5 mm且a：90°和95°处具有矩形腔的圆柱体，观察到最小的涡旋区域。另外，最高阻力系数（C 在整个圆柱体中，在h：37.5 mm且a：90°和95°处具有矩形腔的圆柱体中观察到最小的涡旋区域。另外，最高阻力系数（C对于在h：52.5mm和a：80°处具有方腔的圆柱体，获得_d）值，而对于在h：37.5mm和a：95°处具有方腔的圆柱体，获得最大的阻力系数值。