Detail Heat Transfer Regimes and Hysteresis in Porous Media Convection   Oleh:  Vadasz, Peter Jenis: Article from Bulletin/Magazine Dalam koleksi: Journal of Heat Transfer vol. 123 no. 1 (Feb. 2001), page 145-156. Topik: porous media; heat transfer regimes; hysteresis; porous media convection Ketersediaan Perpustakaan Pusat (Semanggi) Nomor Panggil: JJ90.4 Non-tandon: 1 (dapat dipinjam: 0) Tandon: tidak ada     Lihat Detail Induk Isi artikel Results of an investigation of different heat transfer regimes in porous media convection are presented by using a truncated Galerkin representation of the governing equations that yields the familiar Lorenz equations for the variation of the amplitude in the time domain. The solution to this system is obtained analytically by using a weak non - linear analysis and computationally by using Adomian's decomposition method. Expressions for the averaged Nusselt number are derived for steady, periodic, as well as weak - turbulent (temporal - chaotic) convection. The phenomenon of Hysteresis in the transition from steady to weak-turbulent convection, and backwards, is particularly investigated, identifying analytically its mechanism, which is confirmed by the computational results. While the post - transient chaotic solution in terms of the dependent variables is very sensitive to the initial conditions, the affinity of the averaged values of these variables to initial conditions is very weak. Therefore, long - term predictability of these averaged variables, and in particular the Nusselt number, becomes possible, a result of substantial practical significance. Actually, the only impact that the transition to chaos causes on the predicted results in terms of the averaged heat flux is a minor loss of accuracy. Therefore, the predictability of the results in the sense of the averaged heat flux is not significantly affected by the transition from steady to weak - turbulent convection. The transition point is shown to be very sensitive to a particular scaling of the equations, which leads the solution to an invariant value of steady - state for sub - transitional conditions, a result that affects the transition point in some cases. Opini Anda Klik untuk menuliskan opini Anda tentang koleksi ini! Kembali

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