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The momentary instability of a saturated porous layer with a time‐dependent temperature distribution, and the most unstable disturbance
Author(s) -
Green Theodore
Publication year - 1990
Publication title -
water resources research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.863
H-Index - 217
eISSN - 1944-7973
pISSN - 0043-1397
DOI - 10.1029/wr026i009p02015
Subject(s) - instability , disturbance (geology) , galerkin method , mechanics , stability (learning theory) , constant (computer programming) , materials science , porous medium , porosity , nonlinear system , geology , geotechnical engineering , physics , geomorphology , quantum mechanics , machine learning , computer science , programming language
The stability of fluid with a time‐dependent vertical temperature distribution in a horizontal, saturated porous layer is investigated, using the idea of momentary stability and a Galerkin technique. The most unstable disturbance is found by minimizing the critical Rayleigh number over the Fourier amplitudes of that disturbance, using both an iterative and a simplex procedure. As an example, the case in which an originally linear, stable temperature distribution is changed by lowering the temperature of the upper boundary at a constant rate is examined in detail.