圆柱结构广泛应用于海洋工程，其尾流旋涡脱落产生的波动阻力可能导致涡激振动，影响设备的稳定性。减小圆柱绕流阻力有助于抑制涡激振动，利用仿仙人掌肋和超疏水涂层减阻是近年来发展出的两种高效控制方法，本文结合这两种方法开展水下圆柱绕流减阻的实验。实验结果显示，表面肋能够减小圆柱的阻力，在此基础上叠加超疏水表面可实现进一步减阻。表面肋延长回流区长度而超疏水表面缩短回流区长度，通过本征正交分解计算相位平均流场发现，相较于亲水圆柱，超疏水表面使圆柱尾流剪切层缩短、旋涡卷起更靠近圆柱，从而使回流区长度缩短。总体而言，表面肋和超疏水涂层的结合有效降低了圆柱绕流阻力，为流动控制和减阻技术提供了潜在应用。

The cylindrical structure finds extensive applications in ocean engineering， where the shedding of wake vortices can generate fluctuating drag that may induce vortex-induced vibrations， which can lead to equipment instability. Reducing the flow drag around the cylinder can help suppress vortex-induced vibrations. In recent years， the use of cactus-inspired riblets and superhydrophobic coatings has emerged as two efficient passive control strategies for drag reduction. This study combines these two methods to conduct experiments on drag reduction in underwater cylindrical flow. The experimental results demonstrate that surface riblets can decrease the drag on the cylinder， and the addition of superhydrophobic surfaces can further enhance drag reduction. Surface riblets extend the recirculation region while superhydrophobic surfaces shorten it. By utilizing Proper Orthogonal Decomposition to compute the phase-averaged flow field， it is found that， compared to hydrophilic cylinders， superhydrophobic surfaces lead to a reduction in the cylinder’s wake shear layer and cause the vortex to form closer to the cylinder， thereby shortening the recirculation region. Overall， the combination of surface riblets and superhydrophobic coatings effectively reduces the flow resistance around the cylinder， offering potential applications in flow control and drag reduction technologies.