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Flow pulsation and baffle’s effects on the opposing mixed convection in a vertical channel. (English) Zbl 1188.76247
Summary: This numerical study aims to investigate the effects of a horizontal baffle on the heat transfer characteristics of pulsating opposing mixed convection in a parallel vertical open channel. The influences of the dimensionless pulsating frequency Strouhal number and magnitude \(A\), Prandtl number and baffle position \(L_{b}\) on the velocity and temperature distribution and long-time average Nusselt number \(\langle \overline {Nu}\rangle \) variation for the system at various \(Re\) and \(Gr/Re^{2}\) are explored in detail. Our results show that the channel with both flow pulsation and a baffle gives the best heat transfer. With a larger \(Re\), the inlet flow pulsation dominates the whole velocity field in the channel. \(\langle \overline {Nu}\rangle \) always increases with a larger \(Re\), pulsation magnitude \(A\) and Prandtl number. Maximum \(\langle \overline {Nu}\rangle \) occurs at some specific imposed pulsating frequencies which can be considered to be the natural frequency of the system.

76R05 Forced convection
76R10 Free convection
76M20 Finite difference methods applied to problems in fluid mechanics
80A20 Heat and mass transfer, heat flow (MSC2010)
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