The main objective of this paper is to study the effect of a cold, vertical, arcshaped control plate on the flow characteristics and forced convective heat transfer mechanism across a rotary oscillating, isothermally heated circular cylinder. Twodimensional, unsteady, incompressible, laminar, and viscous flow of a Newtonian, constant property fluid is considered across the cylinder. The simulations are performed with an in-house code for various gap ratios between the control plate and the cylinder (0 ≤ d/R 0 ≤ 3), maximum angular velocity (0.5 ≤ α m ≤ 4) and frequency ratio of oscillation ( f / f 0 = 0.5, 3) at Prandtl number 0.7 and Reynolds number 150. Here, d denotes the gap between the surface of the cylinder and the leading surface of the control plate, R 0 denotes the radius of the cylinder, f is the frequency of oscillation and f 0 is the frequency of natural vortex shedding. d/R 0 = 0 corresponds to the no plate case. Heat transfer and vortex shedding phenomena are discussed in relation to one another. A significant increase in heat transmission is observed for all α m with the gap ratio of d/R 0 = 0.5 and f / f 0 = 0.5. The heat absorption on the surface of the control plate decreases to zero with increasing gap ratio when α m = 0.5 and f / f 0 = 0.5 but never becomes zero when α m = 4 and f / f 0 = 3. Additionally, when compared to the no plate case with (α m , f / f 0 ) = (0.5, 0.5), the maximum peak of the drag coefficient is decreased by 9.877% for the gap ratio of d/R 0 = 3. For α m = 4 and f / f 0 = 3, the smallest gap ratio of d/R 0 = 0.