STABILITY OF FLOWS IN FLUIDIZED-BEDS

We study the linearlized stability of the state of uniform fluidizatio n, within the context of the theory of mixtures. The mixture is assume d to be made up of a classical linearly viscous fluid infused with par ticles. In marked departure from most of the previous studies, we mode l the solid as a granular material and assume a constitutive relation that stems from classical motions in continuum mechanics. The lineariz ed stability analysis of the state of uniform fluidization, in general , for a three-dimensional disturbance leads to an eighth order equatio n for the characteristic whose root implies instability, when positive .