Impact of a Cold Control Plate on Fluid Flow and Heat Transfer across an Isothermally Heated Rotary Oscillating Circular Cylinder
share
The main objective of this paper is to study the effect of a cold, vertical, arc-shaped control plate on the flow characteristics and forced convective heat transfer mechanism across a rotary oscillating, isothermally heated circular cylinder. Two-dimensional, 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=0.5 is found to significantly increase the lift coefficient relative to other cases.
READ FULL TEXT
