A fully coupled method for computing uniform fluctuating flow around bluff bodies

This paper discusses the computation of unsteady two-dimensional incompressible viscous uniform fluctuating flow around bluff bodies. The study focuses on the case where the upstream uniform flow around a circular cylinder is fluctuating in time, harmonically. An implicit second order fully coupled resolution method is developed using a finite volume technique for cell-centered collocated grids. This approach is an alternative to classical segregated approaches, like SIMPLE or PISO. Whereas the segregated methods lead to a sequential resolution of discrete equations and under-relaxation procedures, only one linear system in velocity-pressure is solved using the fully coupled method. The non-linear effects are thus handled better, and the non-linear residues convergence is considerably accelerated. Efficiency and robustness of this numerical technique allows to simulate with accuracy unsteady flows such as uniform fluctuating flow around circular cylinder.