In this paper oscillatory 2-D natural convection from a vertical isothermal wall embedded in a po- rous medium, and originating from the oscillation of longitudinal fluid flow, has been investigated both analytically ...In this paper oscillatory 2-D natural convection from a vertical isothermal wall embedded in a po- rous medium, and originating from the oscillation of longitudinal fluid flow, has been investigated both analytically and numerically. Two asymptotic solutions, valid for large and small values of dimensionless frequency γ respectively, are obtained in the closed form. In the range where the asymptotic solutions break down, numerical results to the governing equations are obtained by local similarity meth- od. Both numerical and analytical results show that pulsatory components of the flow and heat transfer depend only on the parameter γ, and the effect of longitudinal oscillation is to decrease the magnitude or' pulsatory Nusselt number with a phase lag between 0 and 90 deg. A correlation for pulsatory heat trans- fer rates is proposed in the whole range of γ within 3% accuracy compared with the numerical results.展开更多
文摘In this paper oscillatory 2-D natural convection from a vertical isothermal wall embedded in a po- rous medium, and originating from the oscillation of longitudinal fluid flow, has been investigated both analytically and numerically. Two asymptotic solutions, valid for large and small values of dimensionless frequency γ respectively, are obtained in the closed form. In the range where the asymptotic solutions break down, numerical results to the governing equations are obtained by local similarity meth- od. Both numerical and analytical results show that pulsatory components of the flow and heat transfer depend only on the parameter γ, and the effect of longitudinal oscillation is to decrease the magnitude or' pulsatory Nusselt number with a phase lag between 0 and 90 deg. A correlation for pulsatory heat trans- fer rates is proposed in the whole range of γ within 3% accuracy compared with the numerical results.
