On the wake interference effects for flow around tandem bodies

The present study investigates the wake interference effects for flow around two tandem cylinders under the effect of gap spacing ranging from 0.5 to 10. The flow Reynolds number is fixed at 150, and lattice Boltzmann method is used as a numerical tool for this study. The results show that three different regimes exist depending on gap spacing and flow structure mechanism around cylinders: single cylinder body regime, reattachment regime and co-shedding regime. The results also show that in a particular regime multiple flow patterns may coexist and affect the behavior of fluid forces. This study reveals that there exists a critical value of spacing which alters the fluid flow characteristics abruptly. The drag coefficient of second cylinder is negative until critical spacing and becomes positive after that. It is found that when spacing crosses the critical value, both cylinders start shedding vortices and the drag coefficient oscillates. The wake interference effect is found to be dominant at small spacing values which weakens with increment in spacing between cylinders.