Tommaso Ruggeri - Böcker

Ordinary thermodynamics provides reliable results when the thermodynamic fields are smooth, in the sense that there are no steep gradients and no rapid changes. In fluids and gases this is the domain of the equations of Navier-Stokes and Fourier. Extended thermodynamics becomes relevant for rapidly varying and strongly inhomogeneous processes. Thus the propagation of high­ frequency waves, and the shape of shock waves, and the regression of small-scale fluctuation are governed by extended thermodynamics. The field equations of ordinary thermodynamics are parabolic while extended thermodynamics is governed by hyperbolic systems. The main ingredients of extended thermodynamics are • field equations of balance type, • constitutive quantities depending on the present local state and • entropy as a concave function of the state variables. This set of assumptions leads to first order quasi-linear symmetric hyperbolic systems of field equations; it guarantees the well-posedness of initial value problems and finite speeds of propaga­ tion. Several tenets of irreversible thermodynamics had to be changed in subtle ways to make extended thermodynamics work. Thus, the entropy is allowed to depend on nonequilibrium vari­ ables, the entropy flux is a general constitutive quantity, and the equations for stress and heat flux contain inertial terms. New insight is therefore provided into the principle of material frame indifference. With these modifications an elegant formal structure can be set up in which, just as in classical thermostatics, all restrictive conditions--derived from the entropy principle-take the form of integrability conditions.

Physicists firmly believe that the differential equations of nature should be hyperbolic so as to exclude action at a distance; yet the equations of irreversible thermodynamics - those of Navier-Stokes and Fourier - are parabolic. This incompatibility between the expectation of physicists and the classical laws of thermodynamics has prompted the formulation of extended thermodynamics. After describing the motifs and early evolution of this new branch of irreversible thermodynamics, the authors apply the theory to mon-atomic gases, mixtures of gases, relativistic gases, and "gases" of phonons and photons. The discussion brings into perspective the various phenomena called second sound, such as heat propagation, propagation of shear stress and concentration, and the second sound in liquid helium. The formal mathematical structure of extended thermodynamics is exposed and the theory is shown to be fully compatible with the kinetic theory of gases. The study closes with the testing of extended thermodynamics through the exploitation of its predictions for measurements of light scattering and sound propagation.

Rational extended thermodynamics (RET) is the theory that is applicable to nonequilibrium phenomena out of local equilibrium.

Rational extended thermodynamics (RET) is the theory that is applicable to nonequilibrium phenomena out of local equilibrium.

Next, the modern theory of constitutive equations is defined, emphasizing the role of the general principles of material indifference and entropy as criteria for selecting physically acceptable classes of constitutive equations.

L'obiettivo principale di questo libro è presentare un trattamento unificato della termomeccanica dei continui utilizzando l'approccio assiomatico tipico della meccanica razionale. Mentre molti testi di meccanica dei continui si concentrano su tipi specifici di corpi continui, come i corpi solidi deformabili o i fluidi, questo libro adotta una prospettiva generale. Viene presentata la struttura matematica delle leggi di bilancio e delle equazioni costitutive come un insieme coeso, con particolare attenzione alla moderna teoria delle equazioni costitutive. Si sottolineano principi importanti, come il principio di indifferenza materiale e l'interpretazione contemporanea del principio di entropia. Per garantire la coerenza interna, la prima parte del libro affronta questioni relative all'algebra lineare, con particolare attenzione agli operatori lineari all'interno degli spazi vettoriali a dimensione finita. Successivamente, il libro offre un'esplorazione dettagliata delle deformazioni finite dei continui, seguita da una panoramica sulla cinematica. Vengono caratterizzate le varie forze che possono esistere in un continuo, introdotto il tensore degli sforzi e presentate le leggi di bilancio sia in forma euleriana che lagrangiana. Successivamente viene definita la moderna teoria delle equazioni costitutive, sottolineando il ruolo dei principi generali di indifferenza materiale e di entropia come criteri per la selezione delle classi fisicamente accettabili di equazioni costitutive. Le equazioni di campo risultanti sono specializzate per vari casi, tra cui la termoelasticità, i fluidi euleriani, i fluidi di Fourier-Navier‒Stokes e i conduttori rigidi di calore. Nell'ultima parte del libro vengono discussi i sistemi di equazioni alle derivate parziali nella meccanica dei continui, con particolare attenzione ai sistemi iperbolici. Il metodo delle caratteristiche viene introdotto sia nei casi lineari che non lineari, e si discute la necessità di ampliare la classe delle soluzioni introducendo le soluzioni deboli, con le onde d'urto come caso significativo. Come esempio illustrativo di soluzione debole, viene presentato il problema di Riemann per il modello fluidodinamico del traffico veicolare, in cui le automobili sono inizialmente ferme a un semaforo rosso e poi iniziano a muoversi quando il semaforo diventa verde.Questo libro sarà utile non solo per gli studenti di ingegneria, ma anche per gli studenti di altre discipline scientifiche in cui si studiano aspetti della meccanica dei continui. Fornisce l'opportunità di considerare argomenti tradizionalmente distinti in un contesto più ampio e interconnesso.

This book pursues a twofold objective: to introduce the methodologies of Italian Rational Mechanics to an international audience—hoping they may prove valuable to teachers and students in Engineering, Physics, and Mathematics—and to offer essential material for engineering students in Italy whose courses are taught in English. Readers are expected to have a background in Calculus and Linear Algebra, along with a basic familiarity with the fundamental principles of Newtonian Mechanics. Rational Mechanics is a mathematical discipline that spans from Newtonian to analytical and applied mechanics. It follows a rigorous deductive approach and has traditionally provided a foundational framework that bridges mathematics, physics, and engineering. This book builds on the long-standing Italian tradition of teaching Rational Mechanics at the undergraduate level. It is particularly well suited for courses that guide students from first principles to progressively more advanced topics, culminating in the sophisticated modeling of real-world phenomena. Historically, Rational Mechanics has often been the first course in which students of Engineering, Physics, or Mathematics encounter a rigorous and comprehensive framework for mathematical modeling, making its educational value especially significant. The presentation of fundamental concepts is consistently oriented toward applications, with the aim of fostering synergies in teaching, particularly in interdisciplinary contexts. The structure of the book reflects this approach, with special emphasis on sections that are often treated in a more abstract way—such as constraints, the Principle of Virtual Work, d’Alembert’s Principle, and Analytical Mechanics.

In 2013 several scientific activities have been devoted to mathematical researches for the study of planet Earth. The current volume presents a selection of the highly topical issues presented at the workshop “Mathematical Models and Methods for Planet Earth”, held in Roma (Italy), in May 2013. The fields of interest span from impacts of dangerous asteroids to the safeguard from space debris, from climatic changes to monitoring geological events, from the study of tumor growth to sociological problems. In all these fields the mathematical studies play a relevant role as a tool for the analysis of specific topics and as an ingredient of multidisciplinary problems. To investigate these problems we will see many different mathematical tools at work: just to mention some, stochastic processes, PDE, normal forms, chaos theory.

This book is dedicated to the recent developments in RET with the aim to explore polyatomic gas, dense gas and mixture of gases in non-equilibrium. In particular we present the theory of dense gases with 14 fields, which reduces to the Navier-Stokes Fourier classical theory in the parabolic limit. Molecular RET with an arbitrary number of field-variables for polyatomic gases is also discussed and the theory is proved to be perfectly compatible with the kinetic theory in which the distribution function depends on an extra variable that takes into account a molecule’s internal degrees of freedom. Recent results on mixtures of gases with multi-temperature are presented together with a natural definition of the average temperature. The qualitative analysis and in particular, the existence of the global smooth solution and the convergence to equilibrium are also studied by taking into account the fact that the differential systems are symmetric hyperbolic. Applications to shock and soundwaves are analyzed together with light scattering and heat conduction and the results are compared with experimental data.Rational extended thermodynamics (RET) is a thermodynamic theory that is applicable to non-equilibrium phenomena. It is described by differential hyperbolic systems of balance laws with local constitutive equations. As RET has been strictly related to the kinetic theory through the closure method of moment hierarchy associated to the Boltzmann equation, the applicability range of the theory has been restricted within rarefied monatomic gases.The book represents a valuable resource for applied mathematicians, physicists and engineers, offering powerful models for potential applications like satellites reentering the atmosphere, semiconductors and nano-scale phenomena.

In 2013 several scientific activities have been devoted to mathematical researches for the study of planet Earth. The current volume presents a selection of the highly topical issues presented at the workshop “Mathematical Models and Methods for Planet Earth”, held in Roma (Italy), in May 2013. The fields of interest span from impacts of dangerous asteroids to the safeguard from space debris, from climatic changes to monitoring geological events, from the study of tumor growth to sociological problems. In all these fields the mathematical studies play a relevant role as a tool for the analysis of specific topics and as an ingredient of multidisciplinary problems. To investigate these problems we will see many different mathematical tools at work: just to mention some, stochastic processes, PDE, normal forms, chaos theory.

This book is dedicated to the recent developments in RET with the aim to explore polyatomic gas, dense gas and mixture of gases in non-equilibrium.

These lecture notes of the courses presented at the first CIME session 1994 by leading scientists present the state of the art in recent mathematical methods in Nonlinear Wave Propagation.

Questo testo, che giunge ora alla quarta edizione, è stato concepito principalmente per le necessità delle Scuole di Ingegneria, dove la Meccanica Razionale ha il duplice ruolo di introdurre sia alla modellizzazione fisico-matematica rigorosa che a specifiche applicazioni sviluppate poi in altri insegnamenti.

This volume presents an up-to-date overview of some of the most important topics in waves and stability in continuous media. The topics are: Discontinuity and Shock Waves; Linear and Non-Linear Stability in Fluid Dynamics; Kinetic Theories and Comparison with Continuum Models; Propagation and Non-Equilibrium Thermodynamics; and Numerical Applications.

This book contains about 20 invited papers and 40 contributed papers in the research areas of theoretical continuum mechanics, kinetic theory and numerical applications of continuum mechanics. Collectively these papers give a good overview of the activities and developments in these fields in the last few years.The proceedings have been selected for coverage in:• Index to Scientific & Technical Proceedings® (ISTP® / ISI Proceedings)• Index to Scientific & Technical Proceedings (ISTP CDROM version / ISI Proceedings)• CC Proceedings — Engineering & Physical Sciences

The book contains recent contributions in the field of waves propagation and stability in continuous media. In particular, the contributions consider discontinuity and shock waves, stability in fluid dynamics, small parameter problems, kinetic theories towards continuum models, non-equilibrium thermodynamics, and numerical applications.The volume is the fourth in a series published by World Scientific since 1999. The following distinguished authors contribute to the present book: S Bianchini, R Caflish, C Cercignani, Y Choquet-Bruhat, C Dafermos, L Desvillettes, V Giovangigli, H Gouin, I Muller, D Parker, B Straughan, M Sugiyama and W Weiss.

This book brings together several contributions from leading experts in the field of nonlinear wave propagation. This field, which during the last three decades has seen important breakthroughs from the theoretical point of view, has recently acquired increased relevance due to advances in the technology of fluids e.g. at microscale or nanoscale and the recognition of crucial applications to the understanding of biological phenomena.Nonlinear wave theory requires the use of disparate approaches, including formal and rigorous asymptotic methods, Lie group theory, energy methods, numerical analysis, and bifurcation theory. This book presents a unique blend in which different aspects of the theory are enlightened and several real-life applications are investigated. The book will be a valuable resource for applied scientists interested in some of the most recent advances in the theory and in the applications of wave propagation, shock formation, nonequilibrium thermodynamics and energy methods.

This volume is the fifth in a series of proceedings which started in 1999. The contributions include the latest results on the theory of wave propagation, extended thermodynamics, and the stability of the solutions to partial differential equations.