Immersed boundary modeling for interaction of oscillatory flow with cylinder array under effects of flow direction and cylinder arrangement

An array of cylindrical structures are often used as a frame of an offshore platform. The prediction of hydrodynamic loadings on those cylindrical structures due to oscillatory flows is one of the most important issues in the design of those offshore structures. The aim of this study is to apply a direct-forcing immersed boundary method to simulating the oscillatory flow past a circular cylinder array in a square arrangement. The finite volume method was used to solve the Navier–Stokes equations. In this study, the effects of Keulegan–Carpenter (KC) number, oblique flow and the gap among four cylinders were investigated. Numerical results were visualized using vorticity contours so evolutions of oscillatory flow with the cylinder array were presented. Hydrodynamic loadings including in-line and transverse force coefficients were determined and illustrated in the time and spectral domains. Essentially, the proposed direct-forcing immersed boundary approach can be useful for scientists and engineers who would like to understand the interaction of the oscillatory flow with an array of cylinders and to estimate hydrodynamic loadings on the array of cylinders.