Drag suppression for 2D oscillating cylinder with various arrangement of splitters at Re=100: A high-amplitude study with OpenFOAM

The drag suppression for a high-amplitude oscillating cylinder is simulated using various configurations of detached-splitter plates. Governing parameters are the length of splitters (L), the cylinder-splitter gap (G), the amplitude (A), and the frequency of oscillation (f0). The control-volume technique along with the ACMI (arbitrary coupled mesh interface) boundary treatment and dynamic mesh technique are used to capture the high-amplitude boundary movement. It is found that in comparison to the dynamic mesh technique, the ACMI boundary condition is more efficient for highly deforming boundaries between two adjacent domains. Furthermore, it is found that the case with double upstream splitter has the most drag reduction. The lock-on and unlocked regions for a cylinder with diameter of D are identified for dimensionless amplitudes of A/D=0.25 and A/D=0.5, and the minimum values of drag coefficient for various magnitudes of dimensionless gap (G/D) are found. Also, the locked and unlocked configurations play an important role in the drag reduction mechanism. It is concluded that the maximum drop in the drag force occurs for the lock-on condition at dimensionless oscillation frequency of F=1.1. It is concluded that the gap size and the plate length are the least and the most effective quantities, respectively.