2023 Volume 79 Issue 17 Article ID: 23-17005
The ultimate goal of this study is to accurately predict local scour around a cylinder in a wave-current coexisting field. Therefore, in this study, we investigated the non-reflective boundary condition for the coexisting field, including forward and reverse current in a three-dimensional (3D) analysis, and conducted reproduction analyses of the flow regime around a cylinder under the reverse current condition. First, we proposed a non-reflective boundary condition that takes into account the energy decay zone and water volume correction in that zone. Introducing the non-reflective boundary condition into the 3D model showed that a spatially and temporally stable coexisting field could be created. Next, the model was shown to reproduce well, albeit qualitatively, the experimental results on the surface flow around a cylinder as a function of the Keulegan–Carpenter (KC) number under reverse current condition. Finally, the model was used to study the internal flow field around the cylinder and showed that when the KC number is around 7 to 8, a complex and turbulent internal flow field may develop downstream of the cylinder regardless of the forward or reverse current conditions.
