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Title:Wave-packet convection in porous layer with boundary imperfections
Author(s):Riahi, Daniel N.
Subject(s):Wave Packet Convection
Porous Layer
Boundary Imperfections
Abstract:The problem of wave packet thermal convection in a porous layer between two horizontal walls with different mean temperatures is considered when spatially non-uniform temperature is prescribed at the lower wall. The nonlinear problem of three-dimensional convection for the values of the Rayleigh number close to the classical critical value is solved by using multiple scales and perturbation techniques. The preferred pattern of convection is determined by a stability analysis. It is found that for the case of near resonant wavelength excitation regular or non-regular solutions in the form of superpositiion of small scale multi-modal pattern convection and large scale multi-modal (or non-modal) pattern convection can become preferred, provided the wave vectors of modal pattern are contained in the set of wave vectors due to modal form of the boundary imperfections and the non-modal form of the large scale pattern is the same as that due to the boundary imperfections. For the case of non-resonant wavelength excitation some three-dimensional solutions in the form of superposition of small scale multi-modal pattern convection and large scale multi-modal (or nonmodal) pattern convection can be preferred, provided that the wave length of the small scale modulation is not too small. Large scale flow structures are quite different from the small scale flow structures in a number of cases and, in particular, they can exhibit kink and can be non-modal in nature.
Issue Date:1994-06
Publisher:Department of Theoretical and Applied Mechanics. College of Engineering. University of Illinois at Urbana-Champaign
Series/Report:TAM R 757
Genre:Technical Report
Rights Information:Copyright 1994 Board of Trustees of the University of Illinois
Date Available in IDEALS:2021-11-04

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  • Technical Reports - Theoretical and Applied Mechanics (TAM)
    TAM technical reports include manuscripts intended for publication, theses judged to have general interest, notes prepared for short courses, symposia compiled from outstanding undergraduate projects, and reports prepared for research-sponsoring agencies.

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