73198 - Experimental Methods in Aerodynamics

Learning outcomes

Aim of the course is to give the student the fundamental knowledge to plan and execute an experimental campaign in Aero and Fluid-dynamics, as well as the knowledge of the most important instruments and experimental techniques in Aerodynamics. Specifically, at the end of the course the student will be able to:- Determine the relevant variables and non-dimensional parameters for a given fluid-dynamic system; - Choose and/or design the most appropriate experimental setup and measurement instrument - Critically evaluate and analyze the experimental data together with the associated uncertainty.

Course contents

Course contents

The course provides the fundamental knowledge required to plan, perform and critically evaluate experiments in aerodynamics and fluid dynamics. Aerodynamic applications constitute the main reference framework, with selected examples relevant to hydrodynamics and naval engineering.

The course is organised into three main sections.

1. Foundations of Experimental Methods

The first section introduces the experimental process, from the definition of the engineering question to the assessment of data reliability. Topics include experimental planning, dimensional analysis and similarity, measurement chains, calibration, sensor response, data acquisition and sampling, statistical analysis, signal processing and uncertainty evaluation.

Particular attention is given to the relationships between the physical scales of the phenomenon, the characteristics of the measurement system and the quality of the resulting data.

2. Experimental Facilities and Measurement Tools

The second section presents the main facilities and measurement techniques used in experimental fluid dynamics. Topics include wind tunnels and an overview of water tunnels and towing tanks, pressure measurements, force and moment measurements, velocity measurements and selected scalar and surface measurement techniques.

The main techniques are discussed through a common framework including the sensing principle, measurement layout, calibration, spatial and temporal resolution, sensitivity, signal quality, strengths, limitations and representative applications.

3. Experimental Practice, Data Analysis and Reporting

The final section applies the theoretical concepts through practical activities and laboratory experience, including experiments at the CICLoPE research facility. Students are introduced to the main phases of an experimental campaign: setup preparation, calibration, acquisition, data processing, validation, uncertainty assessment and communication of results.

Prior knowledge

Students are expected to possess fundamental knowledge of fluid mechanics and aerodynamics, including the basic principles of internal and external flows and dimensional analysis.

Basic knowledge of probability, statistics and signal analysis is recommended. Familiarity with a scientific computing environment, such as MATLAB or Python, is useful for data processing and visualisation. Review material may be provided for selected prerequisite topics.

Readings/Bibliography

1. Teacher's slides and notes avaliable on e-learning platform

Coursebook: Experimental Aerodynamics by Stefano Discetti and Andrea Ianiro, CRC Press, 2017
ISBN 1498704042, 9781498704045

Suggested literature:

-The Pi-Theorem – applications to Fluid Mechanics,
L.P. Yann; (2012)

-Low-Speed Wind Tunnel Testing, Jewel B. Barlow

- Measurements in Fluid Mechanics, Stavros Tavoularis

- Springer Handbook of Experimental Fluid Mechanics, Cameron Tropea, Alexander Yarin, John Foss

Fundamental aspects of fluid mechanics and Aerodynamics will be treated as prior knowledge. Those in need of reviewing them are recommended to review specific material such as:

- Elements of Fluid Dynamics by G. Buresti

Teaching methods

This course will be held with innovative teaching methdos:

The initial part of the course will be conventional lectures held by the teacher where general and theoretical aspects of Experimental Aeordynamics are indroduced and discussed by the teacher in frontal lectures;

The second part of the course will involve "hands-on" laboratory experience at the international research center CICLoPE. Laboratory exercises are sepcifically designed for the students to learn the best practices in experimental aerodynamics and to apply and verify the theoretical background learnt in the lectures.

The final part of the course the students will present the results of the laboratory experience and learn how to write a scientific report.

The course will be complemented with seminars held by international lecurers on advanced experimental and numerical techniques;

Digital material such as recorded lectures and digital lecture notes, as well as other multimedia material will be available on Virtuale platform.

As concerns the teaching methods of this course unit, all students must attend Module 1, 2 online [https://www.unibo.it/en/services-and-opportunities/health-and-assistance/health-and-safety/online-course-on-health-and-safety-in-study-and-internship-areas], while Module 3 on health and safety is to be attended in class. Information about Module 3 attendance schedule is available on the website of your degree programme.

Assessment methods

The examination is in the form of an oral test held in the following modality: the student will be asked 2 questions from 2 different examiners to ensure ubiased evaluation. For each question, the student will be given some time to wirte down the answer and the main discussion points. This will be followed by an oral discussion with the respective examiner.

The student is expected to clearly explain all the relevant aspect of the experimental or analysis techniques, including physical principles behind the measurement technique, making clear connections between the mathematical aspects discussed in class and the technical issues connected to the application. Fundamental aspects of Aerodynamics, fluid-dynamics will be treaded as necessary prior knowledge.

The exam will be evaluated according to the following general criteria:

- Basic knowledge of the entire course content (e.g. correct statement and use of definitions, good knowledge of all instruments and techniques, etc);

- Ability to make connections between theoretical aspects and engineering solutions; (example: explain why the on board memory of a Camera can limit the frequency resolution or the statistical uncertainty of a PIV experiment)

- Clarity of presentation and synthesis; (Logical organization, legible drawing and schematics, concise argumentation).

Examples of evaluation scale:

18-20: The student shows sufficient knowledge of each topic examined, but is hardly able to make connections and needs considerable help from the examiners in the exposition.

20-26: The student shows a good knowledge of of each topic examined, is able to make some connections between theory and applications with some help from the examiners. The discussion is guided by the examiner.

28-30:The student shows excellent knowledge of of each topic examined, is able to easily make connections between theory and applications without any help from the examiners. The exposition is clear and mainly autonomus.

Teaching tools

PPT slides and lecture notes will be periodically uploaded on Virtuale's platform.

A special section of the platform will be dedicated for sharing additional multi-media material (such as videos, research articles and link to specific websites) that will be uploaded by the teacher or by the students as suggested material.

In addition to the standard lectures, special lectures by invited speakers on advanced measurment techniques will possibly be organized.

Office hours

See the website of Gabriele Bellani