Introduction to Continuum Physics

A.Y. 2023/2024
6
Max ECTS
48
Overall hours
SSD
FIS/01 FIS/02 FIS/03 FIS/04 FIS/05
Language
English
Learning objectives
The course unit is designed to provide the basics of a macroscopic description of continuous media, together with necessary tools such as tensor calculus.
Expected learning outcomes
After attending the course unit, the student will possess the following set of knowledge and skills:
1) Knowledge of macroscopic behavior of matter treated as a continuum within a field theory;
2) Use of tools such as tensor calculus and dimensionless numbers as well as analytical methods for the description of continuous media;
3) Use of mechanics and thermodynamics concepts necessary to continuum dynamics;
4) Knowledge of basic properties, laws and phenomena concerning ideal and real (viscous) fluids and for visco-elasto-plastic solids;
5) Knowledge of basic properties, laws and phenomena concerning heat transport in continuous media;
6) Knowledge of application examples in geophysical, astrophysical and laboratory continuous media.
Single course

This course can be attended as a single course.

Course syllabus and organization

Single session

Responsible
Lesson period
First semester
Course syllabus
INTRODUCTION
Memories from thermodynamics (thermodynamic potentials, Maxwell relations, specific heats, adiabatic processes).
Tensors down to the bone (vectors and tensors; quotient rule, tensor subspaces, geometric decomposition of rank-2 tensors, alternating tensor, duality relations).
General notions on continuous media. Lagrangian and Eulerian approach. Material derivative. Derivative of volume, surface, line integrals. Mass conservation and continuity equation.
Volume and surface forces. Stress tensor, pressure and deviatoric stress tensor, first law of motion for a continuous medium.
STATICS OF IDEAL FLUIDS
Ideal fluid, Euler and entropy equations. Fluid statics: pressure, mechanical equilibrium, stability of the atmosphere. Incompressibility conditions. Statics of incompressible fluids.
FLUID DYNAMICS OF IDEAL FLUIDS
Momentum and energy flux. Bernoulli's theorem and applications. Kelvin's theorem, potential flow, Laplace equation. Gravity waves in ideal fluids, dispersion relations, applications.
REAL (VISCOUS) FLUIDS
Velocity gradient tensor, kinematic interpretation of its geometric decomposition. Cauchy's stress theorem and stress tensor, constitutive equations, Newtonian stress tensor. Navier-Stokes equation. Examples of viscous flows. Similarity laws and dimensionless numbers in the Navier-Stokes equation. Stokes' problem. Oscillatory motions in viscous fluids, damping of gravity waves, surface currents.
Stability under arbitrary and small perturbations. Tangential discontinuities, Kelvin-Helmholtz instability.
DYNAMICS OF CONTINUOUS MEDIA
Constitutive equations for elastic and viscous-elasto-plastic materials; objectivity principle or material frame-indifference. Equation for the incremental linear momentum for a pre-stressed continuum. Elasto-plastic continua: Navier equation and elastic waves.
HEAT EXCHANGE
Heat equation for energy and entropy and second principle of thermodynamics, Clausius-Duhem inequality. Heat equation for incompressible fluids and solids (Fourier equation). Boundary conditions, transient and steady solutions in thermal conduction: examples for the modelling of the Earth's crust. Green's function. Reversibility and irreversibility. Similarity law and dimensionless numbers in the heat equation. The ideal fluid as a limit of the viscous fluids at large global and local Reynolds numbers. Free convection: Boussinesq approximation, Grashof and Rayleigh numbers, Rayleigh-Bénard instability.
Prerequisites for admission
A solid knowledge of the basic notions and tools of mathematics (calculus, algebra and geometry) and of classical physics (mechanics and thermodynamics in particular) is expected.
Teaching methods
Traditional lectures, supplemented by topical seminars. Tutorial activities will be activated, if necessary, for students with a weak background in mathematics and physics.
Teaching Resources
Notes supplied by the teacher, available at the teacher's website
'Fluid Mechanics', L.D. Landau and E.M. Lifshitz (Course of Theoretical Physics, Volume 6), Butterworth-Heinemann
'Elementi di fisica dei continui', G. Parravicini, CUSL
'Mathematics Applied to Continuum Mechanics', L.A. Segel, Dover Publications (or later SIAM edition)
Supplementary material
'Fluid Mechanics', P.K. Kundu and I.M. Cohen (second or later edition), Academic Press
'Fluid Dynamics for Physicists', T.E. Faber, Cambridge University Press
'Introductory Incompressible Fluid Mechanics', F.H. Berkshire, S.J.A. Malham and J.T. Stuart, Cambridge University Press
'Geodynamics', D.L. Turcotte and G. Schubert (second edition), Cambridge University Press
'Theory of Elasticity', L.D. Landau and E.M. Lifshitz (Course of Theoretical Physics, Volume 7), Butterworth-Heinemann
Assessment methods and Criteria
The examination is based on a 45-60 minute discussion. The student must demonstrate an adequate mastery of the physical and mathematical contents of the course, with an accent on the modelling of physical phenomena and on the use of tools such as dimensionless numbers and approximations governed by the hierarchy of the terms concurring to the description of the phenomena under analysis.
FIS/01 - EXPERIMENTAL PHYSICS
FIS/02 - THEORETICAL PHYSICS, MATHEMATICAL MODELS AND METHODS
FIS/03 - PHYSICS OF MATTER
FIS/04 - NUCLEAR AND SUBNUCLEAR PHYSICS
FIS/05 - ASTRONOMY AND ASTROPHYSICS
Lessons: 48 hours
Professor: Maero Giancarlo
Professor(s)
Reception:
by appointment via e-mail
Via Celoria 16: office (DC building, first floor) / laboratory (ex-cyclotron building); online via Zoom/Skype