Flow over rotationally oscillating heated circular cylinder at low Reynolds number

The impact of heat transfer and cylinder rotation on the induced forces due to vortex shedding is numerically studied in this work. The flow is maintained at Reynolds number of 100. Temperature difference of 300K - 900K is used between the cylinder wall and the incoming flow. Transient analysis is conducted to solve URANS using Ansys/Fluent. Rotational oscillations for the cylinder in clockwise and anti-clockwise direction are induced through user-defined-function at the maximum angular displacement of pi/4 and pi/2 radian. The frequency ratio of 0.5, 1, 1.5, and 2 is used. Time history of lift and drag coefficients, rms of lift coefficient, average drag co-efficient, frequency spectrum, normalized Nusselt number and Strouhal number, along with vorticity and tem-perature contours, and pressure plots are presented in this work. The Karman vortex street with 2S vortex shedding pattern is observed for most of the cases, with C(2S) pattern appearing at few cases. It is found that the heat transfer causes damping in the amplitude and frequency of the drag and lift coefficients. Whereas the oscillatory rotation of cylinder results in an increase in the amplitude of the drag and lift coefficients especially at the lock-on condition, and also induces their amplitude modulation.