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Papers by Roney Thompson

Journal of Non-newtonian Fluid Mechanics, 1999

International Journal of Advances in Engineering Sciences and Applied Mathematics, 2009

Flow classification is a broad field that can be approached in a variety of forms. In the present... more Flow classification is a broad field that can be approached in a variety of forms. In the present context, the basic idea is to search for a criterion that enables one to establish rheological material functions in steady and unsteady flows in the Lagrangean sense. This is still an open problem but there is some recent progress on the subject that is worthy of review. In this connection, the idea of persistence of straining has been used to understand and interpret simple flows and complex flow fields. We present a brief history of persistence of straining and the attempts to capture this concept in a rational definition.We also show some other criteria present in the literature to capture an analogous concept involving non-kinematic quantities as primitive for the flow classification. In this last type of criterion, special attention is given to persistence of stressing. New perspectives on anisotropic and history related measurers are also given.

Rheologica Acta, 2008

IntroductionThe article by Brunn (2006) compares three flow classification parameters available i... more IntroductionThe article by Brunn (2006) compares three flow classification parameters available in the literature, namely, the ones proposed by Astarita (1979) (F1), Thompson and de Souza Mendes (2005a) (F2), and Larson (1985) (F3). This comparison is done from the perspective of the flow classification criterion of Tanner and Huilgol (1975). He concludes that the criteria are based on 2-D flows and that other quantities are needed to fully classify motions.Philosophies of the flow classification criteriaBrunn (2006) points out that, of the flow classification parameters cited above, no one alone is capable of translating the strong/weak classification of Tanner and Huilgol (1975) into quantitative form. His line of argument implies that the strong/weak concept is the benchmark criterion, and hence any other criterion that is not in total conformity with it is therefore incorrect. He seems to have missed the fact that the three parameters analyzed in Brunn (2006) rely on a different ph ...