Heat Transfer Characteristics of Flow over a Circular Cylinder with an Upstream Control Rod in Wall Vicinity

Abstract

Two-dimensional flow over a circular cylinder placed in-line behind a control rod of the same diameter is studied with and without the influence of a plane wall. Thermal patterns observed during various vortex shedding modes are discussed in detail. POD analysis of temperature data reveals that, with the decrease in wall height, modal structures are moved closer to the cylinder surface, which increases the heat transfer fluctuation. The plane wall increases the heat transfer from the bottom surface of the cylinder and decreases the heat transfer from the top surface, while the rotation of control rod contributes in an opposite manner. As the cylinder is moved closer to the wall, the time-averaged Nusselt number increases for a stationary control rod. In the case of a rotating control rod, the rotation of the control rod acts in the opposite sense to nullify this wall effect.

Acknowledgments

We would like to acknowledge the High Performance Computing Environment (HPCE), IIT Madras for providing computational resources.

Notes

ω: angular velocity of control rod, D: diameter of cylinder and control rod, S: separation distance between the surface of the control rod and cylinder, and H: wall height measured from the wall to the bottom surface of the cylinder.

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