35325 - Advanced Fluid Mechanics (2nd cycle)

Learning outcomes

The student becomes familiar with the main experimental measurement techniques and aerodynamic apparatus. He/she also approaches modern and advanced experimental techniques for the analysis of wall bounded turbulent flows. By applying these concepts he/she is capable of designing an experiment, acquiring and processing the data and validating the results by means of an uncertainty analysis.

Course contents

1. FLUIDS AND THEIR MOTION The physics of fluids. Equations of motion. Buckingham theorem.

2. MEASUREMENT. Introduction. Measurement chain. Sensor and transducers. Resolution and frequency response. Noise. Acquisition and data-processing.

3. UNCERTAINTY ANALYSIS Introduction. Basic concepts and definitions. Errors and Uncertainties in the Measured Variable. Gaussian distribution. Central limit theorem. Definition of mean and variance of a sample population. Sample population confidence intervals and rejection of outliers. Uncertainty in a Result Determined from Multiple Variables. Taylor Series Method for propagation of uncertainties. Monte-Carlo methods. General and Detailed Uncertainty Analysis. Experiment planning. Repetition and replication. Additional considerations. Validation of Simulations. Verification & Validation. Data Analysis, Regression and Reporting. Regression model uncertainty. Least square methods. Calibration errors.

4. WIND TUNNELS. Introductory remarks. Different types and features. The basic elements of a wind tunnel. The aerodynamic design. Estimated losses. Wind tunnels for special applications. The test chamber. Different types. The blockage. Corrections.

5. MEASUREMENT METHODS. Pressure measurements. Basic definitions. Pressure sensors. Surface measurements. Velocity measurements using pressure. The Prandtl probe. Pressure transducers. Pressure Scanners. Velocity measurements. Hot-wire anemometry. Methodologies for single, double and triple wires. Vorticity probes. Laser-Doppler anemometers. Measurements by Particle Image Velocimetry. Elements of Stereo-PIV, time resolved and holographic.

6. SIGNAL ANALYSIS. Introduction. Frequency Analysis. Spectrum and Fourier analysis. Wavelet analysis. POD decomposition.

7. THE “CICLoPE” PROJECT. Introduction. Issues related to the measurement of wall turbulence. Problems connected with the measurement of flows at high Reynolds number. Corrections for pressure measurements and hot-wire. Measurements of shear stress at the wall. Oil-film technique.

Readings/Bibliography

Measurements in Fluid Mechanics –  S. Tavoularis  – Cambridge University Press – ISBN 0070697124

Aerodinamica Sperimentale – Lecture notes

Elements of Fluid Dynamics – G. Buresti – Imperial College Press

Random Data: Analysis and Measurement procedures – J.S. Bendat & A. G. Piersol – Wiley

Experimentation, Validation, and Uncertainty Analysis for Engineers  - Hugh W. Coleman, W. Glenn Steele - Wiley; 3 edition - ISBN-13: 978-0470168882

Teaching methods

Lectures and exercises given by the docent. During the course, seminars and integrative courses, given by highly distinguished lecturers, will be organised. They will be focused on specific topics in Experimental Aerodynamics for wall bounded turbulent flows. These arguments will be part of the program and can be the part of the final exam.

Assessment methods

The exam consists of a single session in which the student should answer firstly a written test. The correction of the test will be when the student have finished and will be the base for further oral questions on the subject. The student must show a sufficient skill in writing down and commenting the mathematical and physical models as well as the different experimental techniques.

Teaching tools

Blackboard and power point presentations. Matlab exercise. Exercise in the aerodynamic laboratory.  

Office hours

See the website of Alessandro Talamelli

See the website of Gabriele Bellani