Viscous heating and instability of the adiabatic buoyant flows in a horizontal channel

A. Barletta, M. Celli, D. A.S. Rees

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4 Citations (SciVal)


The stability of buoyant flows occurring in the mixed convection regime for a viscous fluid in a horizontal plane-parallel channel with adiabatic walls is investigated. The basic flow features a parallel velocity field under stationary state conditions. There exists a duality of flows, for every prescribed value of the mass flow rate across the channel cross-section, caused by the combined actions of viscous dissipation and the buoyancy force. As pointed out in a previous study, only the primary branch of the dual solutions is compatible with the Oberbeck-Boussinesq approximation. Thus, the stability analysis will be focused on the stability of such flows. The onset of the thermal instability with small-amplitude perturbations of the basic flow is investigated by assuming a very large Prandtl number, which is equivalent to a creeping flow regime. The neutral stability curves and the critical parametric conditions for the onset of instability are determined numerically.

Original languageEnglish
Article number033111
Number of pages35
JournalPhysics of Fluids
Issue number3
Early online date14 Mar 2023
Publication statusPublished - 31 Mar 2023

Bibliographical note

Funding Information:
The authors acknowledge financial support from Italian Ministry of Education, University and Research (MIUR) Grant No. PRIN 2017F7KZWS.

ASJC Scopus subject areas

  • Computational Mechanics
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering
  • Fluid Flow and Transfer Processes


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