Influence of upstream cylinder on flow-induced vibration and heat transfer of downstream cylinder

The effect of upstream stationary cylinder on the flow-induced vibration (FIV) and heat transfer characteristics of downstream elastically supported cylinder was investigated numerically. The influence of reduced velocity (U*) and gap between two cylinders (S/D) on the vortex formation, temperature distribution, FIV response, and Nusselt number was studied. The results show that the FIV of cylinder has positive and negative effects on heat transfer. When U* is low, the heat transfer of the downstream oscillatory cylinder is weakened. As U* increases, the FIV will gradually enhance the heat transfer. When S/D = 1.1–3.0, the FIV of the downstream oscillator can drastically enhance the heat exchange of the upstream one, and the average Nusselt number (NuA) of the upstream cylinder can increase by 19.51%. When S/D rises to 4 or 5, the change of the boundary layer separation point of two cylinders is similar and the heat transfer characteristics of the upstream cylinder are about the same as the cases when both cylinders are stationary. For the downstream cylinder, the heat transfer will be significantly strengthened, and NuA can increase by up to 150.42%.