OVERVIEW

The course is divided into two distinct but interacting parts: the first concerns the theoretical foundations of turbulence; the second concerns the introduction of CFD-type methods and application to problems of aeronautical / aero-elastic interest. The two parts can not survive independently: the absence of theoretical bases of turbulence makes the use of CFD techniques like real black-boxes, whose outputs can be out of control to an untrained user.

AIMS AND CONTENT

LEARNING OUTCOMES

The aim of the course is to provide key notions on hydrodynamics stability and  transition  to turbulence (mainly for the case of boundary layer flows) . The fully developed turbulence regime will be investigated also exploiting the Reynolds averaged Navier-Stokes equations. Basic notions of numerical modelling will be also provided.

AIMS AND LEARNING OUTCOMES

The course aims to introduce the key concepts of hydrodynamic stability and transition to turbulence.
The study of turbulence will also be based on the Reynolds Averaged Navier-Stokes Equations (RANS) and Large-eddy simulation (LES). The CFD approach will also be introduced  with special emphasis on the open source model, OpenFOAM, of which we will show the main characteristics via a specific training in the informatics lab.

TEACHING METHODS

The course is based on 60 hours of frontal lectures, 40 dedicated to  theory and 20 to exercises to fix key theoretical aspects.  There will be one midterm written examination and a final written examination followed by an oral examination in the case both written examinations were successful.Instructors can be contacted by the students for questions and clarifications during office hours during the semester or by arrangement.

SYLLABUS/CONTENT

A brief overview of basic concepts of fluid mechanics;

Inviscid and viscous stability: Rayleigh, Orr-Sommerfeld and Squires equations

Transition to turbulence through the dynamical system approach;

Fully developed turbulence (FDT): statistical description;

Proliferation of  degrees of freedom in FDT: need for coarse-grained models of turbulence;

RANS, LES and DNS strategies;

Quick tour on numerical issues in turbulence.

The Open Source CFD model OpenFoam: generalities and exercises in the informatics room.

RECOMMENDED READING/BIBLIOGRAPHY

P.J. Schmid & D.S. Henningson, Stability and Transition in Shear Flows, Springer, 2001

U. Frisch, Turbulence, Cambridge Univ. Press. 1995;

E. Ott, Chaos in Dynamical Systems, Cambridge Univ. Press. 1993;

T. Bohr et al,  Dynamical system approach to turbulence, Cambridge Univ. Press. 1998;

J. M. McDonough, Introductory lectures on Turbulence, University of Kentucky, 2004

TEACHERS AND EXAM BOARD

Exam Board

ANDREA MAZZINO (President)

ALESSANDRO BOTTARO

JAN OSCAR PRALITS

LESSONS

Class schedule

TRANSITION AND TURBULENCE

EXAMS

EXAM DESCRIPTION

  After the semester, examinations will consist of a written examination plus an oral examination.

ASSESSMENT METHODS

Written exam (mandatory) and oral exam (optional)

Exam schedule

FURTHER INFORMATION

Pre-requisites :

Basic knowledge of Fluid Mechanics.