Local Scouring Around a Cylinder by Current Flow

Previous studies on scouring around circular cylinders have been limited to specific conditions owing to the significant variation in ground properties across regions and the incomplete understanding of the fluid-ground interaction mechanism. Existing experimental equations focused on river piers and only considered cylinder diameter, neglecting flow velocity and soil grain size. Consequently, these equations may not be applicable to offshore scouring, where ground characteristics and sea conditions vary widely. In this study, we conducted experiments with varying flow velocities and grain sizes to establish an equation for estimating flow-induced scouring depth in offshore areas. Scouring experiments were performed on a scaled monopole model at ratios of 1/13, 1/65, and 1/130 to investigate the effects of flow velocity and soil grain size. Based on the results, we derived an estimation equation that incorporates the number of shields as a variable. Unlike previous prediction equations, this equation considers the dependencies of scouring on grain size and flow velocity. By organizing the results accordingly, we provide a more comprehensive estimation approach for offshore flow-induced scouring.