The effect of inclination angle on the flow characteristics of tandem bluff plates

Abstract

The flow around bluff bodies in tandem is of significant interest due to its broad range of applications. Past studies have investigated the effect of common geometry configurations such as bluff plates and cylinders and found that flow characteristics varied significantly dependent upon certain geometrical parameters such as bluff body size or spacing ratios. This work explores an unobserved area to determine the effect of inclination angle on the flow around tandem bluff bodies due to an expected change in the pattern of the shed vortices. Specifically, key flow characteristics such as velocity fluctuations and drag are investigated for a pair of flat plates with equal dimensions at a Reynolds number of 54,000. The results are complimented by numerical modelling through computational fluid dynamics using Large Eddy Simulation, where vortex structures are visualized and quantitative drag are validated for. Strouhal number plots show that the inclination angle has a significant effect on the flow interactions between tandem bluff plates, and that when inclined, known transitions between flow regimes no longer occur. The results show that when the shear layer from an upstream bluff body does not meet at the downstream body at any location, a drag reduction is not possible a