Mixed Convective Flow Past Reverse Doublet like Rotating Side by Side Cylinders

Abstract

The flow unsteadiness and the consequent evolution of the vortex shedding for flows around bluff objects are significantly important in fluid dynamics. Rotating the bluff objects may help in controlling such flow instabilities. Depending on the rotational speed, the unsteady flow may be transfigured into a steady pattern. On the other hand, multiple objects placed transverse to the incoming flow have destabilizing wake interactions. The instability even gets amplified with the introduction of thermal buoyancy. Under such conditions, the rotation plays an important role in stabilizing the wake dynamics. In view of the above, the present study aims to numerically investigate the wake and the thermal characteristics around a pair of circular cylinders arranged in side-by-side fashion in an unconfined medium. The top and the bottom cylinders are rotated in the counterclockwise and the clockwise directions, respectively, replicating a reverse doublet like configuration. The Reynolds and the Prandtl numbers are fixed at 100 and 0.71, respectively. The effect of the rotation on the flow instability is studied for Richardson number 0 to 1. The computations are performed using a finite volume method for the dimensionless cylinder spacings 0.7, 1.5, 3.0, and 5.0. The unsteady and the steady attributes are examined using the vorticity, isotherm-streamline contours, and lift signals. Finally, a regime diagram is constructed to exhibit the critical rotational speeds at which the flow becomes steady for various cylinder spacings.

Acknowledgements

N.V.V. Krishna Chaitanya gratefully acknowledges the financial support from Council of Scientific and Industrial Research (CSIR-HRDG), India through CSIR – Senior Research Fellowship scheme with award no. 31/0019(11395)/2021-EMR-I.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Notes on contributors

Nallacheruvu Venkata Vijaya Krishna Chaitanya

Nallacheruvu Venkata Vijaya Krishna Chaitanya is currently working as a senior research fellow under the guidance of Dr. Dipankar Chatterjee at Academy of Scientific and Innovative Research associated with Central Mechanical Engineering Research Institute, India. He received his M. Tech degree in computational fluid dynamics from University of Petroleum and Energy Studies, India, and B. Tech degree in Mechanical Engineering from K L University, India. His present research includes wake vortex dynamics and control of instabilities around bluff bodies under forced and mixed convective transport.

Dipankar Chatterjee

Dipankar Chatterjee is a Senior Principal Scientist at CSIR-Central Mechanical Engineering Research Institute, India and Professor in Academy of Scientific and Innovative Research, India. Earlier he was associated with LPMI, Arts etMétiers Paris Tech, France as a post-doctoral researcher. He received his Ph.D. from the Department of Aerospace Engineering, Indian Institute of Technology Kharagpur, India. He has published more than 125 international journal papers. His main interests are computational modeling of fluid flow and heat transfer over bluff objects, turbulence, phase change and reactive flow process modeling, lattice Boltzmann modeling and electromagnetohydrodynamic interactions in macro and micro flows.