Effect of downstream cylinder rotation on wake dynamics of two inline circular cylinders

Two-dimensional numerical investigations have been carried out to study flow past two inline circular cylinders with stationary upstream and rotating downstream cylinder. Computations are performed using commercial software ANSYS Fluent 16.0 for a fixed Reynolds number (Re) of 150 to study wake characteristics unsteady laminar flow. Optimal values of spacing between cylinders and downstream cylinder rotation speed have been identified, confirming the suitability of such an arrangement for drag reduction and flow control. Steady and unsteady features of the wake have been examined with the help of vorticity contours, lift and drag coefficients, their signals and spectra. Interesting phenomena that include multiple transitions in the temporal behavior of the flow and appearance of circulation zone, its development, stabilization, and transformation have been elaborated in this study.