On the flow characteristics of a four square-cylinder array at a 45° incidence angle and low Re

The four-cylinder model is widely applied in many engineering projects immersed in unsteady flow. However, its flow hydrodynamic characteristics are not fully understood. In the present work, the finite volume method is adopted in spatial discretization, while the SIMPLE algorithm in association with the non-iterative fractional step method is utilized to address the governing Navier–Stokes equation. Four equilaterally arranged cylinders at a flow incidence angle of 45° (α = 45°) are numerically simulated, and the corresponding Reynolds number ranges from 40 to 160. The accuracy and applicability of the numerical method employed in this investigation are verified by flow over a single cylinder. In the current work, the hydrodynamic characteristics, flow field characteristics, and structural vibration characteristics of cylinders are systematically investigated by changing the spacing ratio L/D (L/D = 1.2–4.0) and the Reynolds number. Numerical results show that the four cylinders have respective features and interaction effects. There are approximately eight wake flow patterns influenced by the spacing ratio. In addition, the numerical results also indicate that fluid dynamics are determined by flow patterns. These results can be a reference in engineering design, such as for ocean platforms with four cylindrical columns.