Thermal Buoyancy as a Wake Controller: Coupled Wake Dynamics and Heat Transfer in Mixed Convection
Year: 2026
Type: article
Abstract: The dominance and impact of strong thermal buoyancy on the hydrodynamic and thermal properties of a horizontally heated circular cylinder immersed in a vertically ascending laminar flow stream have been numerically investigated. The dynamics are determined by numerically solving the standard energy and two-dimensional laminar Navier-Stokes equations and by incorporating buoyancy through the Boussinesq approximation in the mixed convection co-flow configuration. The Reynolds number is varied within the range of 80 ≤ Re ≤ 160, while the Prandtl number is maintained constant at 0.71. The influ- ence of thermal buoyancy on the system is assessed by adjusting the Richardson number within the range of 0 to 1. The code is validated against and compared against several numerical and experimental results, and its strong prediction capabilities are confirmed. This study examines a significantly observed von Kármán vortices and its vanishing at above a threshold Richardson number, which has been identified as the critical Richardson number. This study provides a detailed explanation of a new phenomenon, termed ‘vortex switching’, which arises from the interaction between inertia-buoyancy interactions. The study showcases representative patterns of vorticity, streamlines, and isotherms, while also plotting the average Nusselt numbers against the Richardson number for various Reynolds numbers. Furthermore, it offers a correlation for the changes in wake width, recirculation bubble length, and vortex switching length, which are essential for optimising design and enhancing thermal efficiency. Lastly, the thermal characteristics provide deeper insights into the impact of superimposed thermal buoyancy on wake flow and heat transfer rates.
Source: Symmetry
DOI: 10.3390/sym18081401
Institutions: Amrita Vishwa Vidyapeetham, Sejong University
Language: English
Subfield: Computational Mechanics
Field: Engineering
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $2,896
OpenAlex ID: W7203820135