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- Mechanism of nonlinear flow pattern selection in moderately non-Boussinesq mixed convection
- Suslov, Sergey A.
- Nonlinear (non-Boussinesq) variations in fluid's density, viscosity, and thermal conductivity caused by a large temperature gradient in a flow domain lead to a wide variety of instability phenomena in mixed convection channel flow of a simple gas such as air. It is known that in strongly nonisothermal flows, the instabilities and the resulting flow patterns are caused by competing buoyancy and shear effects [see S. A. Suslov and S. Paolucci, J. Fluid Mech. 302, 91 (1995)]. However, as is the case in the Boussinesq limit of small temperature gradients, in moderately non-Boussinesq regimes, only a shear instability mechanism is active. Yet in contrast to Boussinesq flows, multiple instability modes are still detected. By reducing the system of full governing Navier-Stokes equations to a dynamical system of coupled Landau-type disturbance amplitude equations we compute a comprehensive parametric map of various shear-driven instabilities observed in a representative moderately non-Boussinesq regime. Subsequently, we analyze nonlinear interaction of unstable modes and reveal physical reasons for their appearance.
- Publication type
- Journal article
- Research centre
- Swinburne University of Technology. Faculty of Engineering and Industrial Sciences
- Physical Review E, Vol. 81, no. 2 (Feb 2010)
- Publication year
- FOR Code(s)
- 01 Mathematical Sciences; 02 Physical Sciences; 09 Engineering
- Boussinesq limit; Flow patterns; Fluid properties; Temperature gradients
- American Physical Society
- Publisher URL
- Copyright © 2010 The American Physical Society. Published version of the paper reproduced here with the kind permission of the publisher for non-commercial purposes only.
- Full text
- Peer reviewed