Abstract
Flow driven by an externally imposed pressure gradient in a vertical porous channel is analysed. The combined effects of viscous dissipation and thermal buoyancy are taken into account. These effects yield a basic mixed convection regime given by dual flow branches. Duality of flow emerges for a given vertical pressure gradient. In the case of downward pressure gradient, i.e. upward mean flow, dual solutions coincide when the intensity of the downward pressure gradient attains a maximum. Above this maximum no stationary and parallel flow solution exists. A nonlinear stability analysis of the dual solution branches is carried out limited to parallel flow perturbations. This analysis is sufficient to prove that one of the dual solution branches is unstable. The evolution in time of a solution in the unstable branch is also studied by a direct numerical solution of the governing equation.
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Barletta, A., Miklavčič, M.: On fully developed mixed convection with viscous dissipation in a vertical channel and its stability. Z. Angew. Math. Mech. 96, 1457–1466 (2016)
Barletta, A., Magyari, E., Keller, B.: Dual mixed convection flows in a vertical channel. Int. J. Heat Mass Transf. 48, 4835–4845 (2005)
Barletta, A., Magyari, E., Pop, I., Storesletten, L.: Mixed convection with viscous dissipation in a vertical channel filled with a porous medium. Acta Mech. 194, 123–140 (2007)
Barletta, A., Lazzari, S., Magyari, E.: Buoyant Poiseuille–Couette flow with viscous dissipation in a vertical channel. Z. Angew. Math. Physik 59, 1039–1056 (2008)
Barletta, A.: Local energy balance, specific heats and the Oberbeck–Boussinesq approximation. Int. J. Heat Mass Transf. 52, 5266–5270 (2009)
Barletta, A.: On the thermal instability induced by viscous dissipation. Int. J. Therm. Sci. 88, 238–247 (2015)
Barletta, A., Rees, D.A.S.: Stability analysis of dual adiabatic flows in a horizontal porous layer. Int. J. Heat Mass Transf. 52, 2300–2310 (2009)
Barletta, A., Zanchini, E.: On the choice of the reference temperature for fully-developed mixed convection in a vertical channel. Int. J. Heat Mass Transf. 42, 3169–3181 (1999)
Celli, M., Alves, L.S. de B., Barletta, A.: Nonlinear stability analysis of Darcy’s flow with viscous heating. Proc. R. Soc. A 472, 20160036 (2016)
Henry, D.: Geometric Theory of Semilinear Parabolic Equations. Springer, Berlin (1981)
Joseph, D.D.: Variable viscosity effects on the flow and stability of flow in channels and pipes. Phys. Fluids 7, 1761–1771 (1964)
Joseph, D.D.: Stability of frictionally-heated flow. Phys. Fluids 8, 2195–2200 (1965)
Miklavčič, M.: Applied Functional Analysis and Partial Differential Equations. World Scientific Publishing Co., Inc., River Edge (1998)
Miklavčič, M.: Stability analysis of some fully developed mixed convection flows in a vertical channel. Z. Angew. Math. Mech. 95, 982–986 (2015)
Miklavčič, M., Wang, C.Y.: Completely passive natural convection. Z. Angew. Math. Mech. 91, 601–606 (2011)
Nield, D.A., Barletta, A., Celli, M.: The effect of viscous dissipation on the onset of convection in an inclined porous layer. J. Fluid Mech. 679, 544–558 (2011)
Nield, D.A., Bejan, A.: Convection in Porous Media, 4th edn. Springer, New York (2013)
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Appendix
Appendix
If we multiply Eq. (8a) by \(T'\) and integrate, we obtain
after noting that \(T'(0)=0\). If we use Eq. (17) and scale with \(T(0)-T_m-P\), we obtain two branches.
When \(T(0)-T_m-P>0\), one can describe T parametrically as follows:
where \(0\le s<s_\mathrm{max}=\int _0^\infty (3-3x^2+x^4)^{-1/2}\mathrm{d}x=2.103\) and \(\varphi \) is defined on \([0,s_\mathrm{max})\) by
In this case
These solutions make up the entire upper branch in Fig. 1 and the piece between C and A on the lower branch.
When \(T(0)-T_m-P<0\) one can describe T parametrically as follows:
where \(0\le s<z_\mathrm{max}=\int _0^\infty (3+3x^2+x^4)^{-1/2}\mathrm{d}x=1.214\) and \(\psi \) is defined on \([0,z_\mathrm{max})\) by
In this case
These solutions make up the lower branch in Fig. 1 without the piece between C and A.
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Barletta, A., Miklavčič, M. Instability of fully developed mixed convection with viscous dissipation in a vertical porous channel. Transp Porous Med 117, 337–347 (2017). https://doi.org/10.1007/s11242-017-0836-x
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DOI: https://doi.org/10.1007/s11242-017-0836-x