A Variational Method For Investigating The Stability Of Parallel Flows

A Variational Method for Investigating the Stability of Parallel Flows

Recent Developments in Thermomechanics of Solids

The main objective of the contributions contained in this volume is to present the thermodynamic foundations of the response of elastic and dissipative materials. In particular, the governing equations of non linear thermoelasticity and thermoinelasticity as well as the basic properties of these equations as resulting from the primary assumptions of continuum thermodynamics are derived. The global formulation of thermodynamics of continua is discussed. A special attention is paid to the properties of the balance equations on a singular surface. The possible forms of the second law of thermodynamics are discussed within the frame work ofaxiomatic thermodynamics. Furthermore, the thermodynamiG requirements for differ ent kinds of materials are examined. The secondary purpose of the Course was to discuss some connections between rational and classical formulations of the principles of thermodynamics. The present volume contains the texts of three (of the four delivered) Course lectures. I hope it will constitute a useful source of information on the problems presented and discussed in Udine. Special thanks are due to the International Centre for Mechanical Sciences whose direction encouraged us to prepare and to deliver the lectures.

Convection in Liquids

Both of the authors of this book are disciples and collaborators of the Brussels school of thermodynamics. Their particular domain of competence is the application of numerical methods to the many highly nonlinear problems which have arisen in the context of recent developments in the thermodynamics of irreversi ble processes: stability of states far from equilibrium, search for marginal critical states, bifwrcation phenomena, multiple stationnary states, dissipative structures, etc. These problems cannot in general be handled using only the clas sical and mathematically rigorous methods of the theory of differential, partial differential, and int~grodifferential equations. The present authors demonstrate how approximate methods, re lyi ng usually on powerful computers, lead to significant progress in these areas, if one is prepa red to accept a certain lack of rigor, such as, for example, the lack of proof for the convergence of the series used in the context of problems which are not self adjoint, nor even linear. The results thus obtained must consequently be submit ted to an exacting confrontation with experimental observations. - Even though, the '1 imited information obtained concerning the, often unsuspec ted, mechanisms underlying the observed phenomena is both precious and frequently sufficient. This information results from the properties of the trial functions best suited to the constraints of the problem such as the initial, boundary, and "feedback" conditions, and the analysis of their behavior in the course of the evolution of the system.