Aerodynamics

Duration

27h Th, 25h Pr, 2h Labo., 25h Proj.

Number of credits

Lecturer

Thomas Andrianne, Vincent Terrapon

Language(s) of instruction

English language

Organisation and examination

Teaching in the first semester, review in January

Schedule

Schedule online

Units courses prerequisite and corequisite

Prerequisite or corequisite units are presented within each program

Learning unit contents

Aerodynamics is the study of fluid flows around or within solid bodies. One of the major objectives of aerodynamics is to predict the forces and moments that are exerted by the fluid on the body, or to predict the heat transfers between the fluid and the body. Classically, aerodynamics has mostly focused on the calculation of lift and drag forces on simple airfoils or even complete aircrafts. Determining the aerodynamic forces and moments are a critical step in the design of an aircraft. Aerodynamics is thus an essential topic in the curriculum of aerospace engineers. 
This course presents the most fundamental aspects of aerodynamics. It focuses mostly on low-speed (incompressible) aerodynamics, but also briefly introduces some elements of compressible aerodynamics. Following topics are covered:

• Aerodynamic forces and moments: lift and drag, pitching moment, airfoil polar, aerodynamic center, center of pressure
• Incompressible potential flows, singularities (vortex, source, doublet), d'Alembert principle, circulation
• Superposition of fundamental solutions, Rankine oval, lifting cylinder, Kutta-Joukowski theorem, conformal mapping, complex formalism, Joukowsky airfoil
• Thin airfoil theory: line distribution of singularities, effect of thickness and camber, Kutta condition
• Panel methods: potential-based, vortex-based, source-based, equivalence between source, doublet and vortex-based methods
• 3D wings: vortex sheet, Prandtl lifting line theory for large aspect ratio wings, distribution of circulation, induced drag, downwash velocity, elliptic lift distribution, optimal wing, general lift distribution
• Boundary layers: concepts and definitions, boundary conditions, thickness, von Karman integral equation, flow separation and airfoil stall, transition to turbulence
• Laminar boundary layer: self-similar solution (Blasius, Falkner-Skan), Pohlhaussen method, Thwaites method
• Turbulent boundary layer: transition, characteristics, Reynolds-averaging, Head method, log law
• Compressible aerodynamics: compressible potential flow, Prandtl-Glauert equation, flow past a thin airfoil (subsonic, transonic, supersonic)
• Application to vehicle aerodynamics

Learning outcomes of the learning unit

At the end of the course, the students should be able to:

• Compute the aerodynamic forces and moments on a profile from a velocity or pressure distribution
• Differentiate between the sources of drag, their cause and characteristics
• Simplify important equations using dimensional analysis
• Calculate the potential flow around a profile using the method of singularities and conformal mapping
• Calculate the aerodynamic forces on a airfoil profile using the thin airfoil theory
• Understand the link between singularities and panel methods
• Calculate the inviscid aerodynamic forces on a three-dimensional wing from its two-dimensional characteristics
• Calculate the boundary layer from the potential flow solution
• Determine the best approach to compute the boundary layer (self-similar profile, integral method, ...)
• Compare experimental measurements, with theoretical and/or numerical results
• Differentiate between the physics of laminar and turbulent flows
• Determine the characteristics of transition to turbulence and flow separation from the pressure distribution and Reynolds number
• Average important equations using Reynolds approach
• Estimate the aerodynamic forces in the supersonic and transsonic regimes for thin airfoils
• Apply the concepts seen in class to other topics

Prerequisite knowledge and skills

To efficiently follow this course, it is preferable to have some basic knowledge in fluid mechanics (e.g., MECA0025 "Mécanique des fluides") and in mathematics (e.g., MATH0007 "Analyse mathématique II").

Planned learning activities and teaching methods

Each week, the course relies on a formal lecture, a problem set and an informal discussion about the theory and practical exercises.
The lecture, taught by the instructors, is in the form of a weekly podcast that the students should watch at home. These podcasts are about 2 hours long (except the first one that is longer). They introduce, develop and explain the important theoretical concepts of the course. Podcasts and lecture notes are available on the course website.
Problem sets are also posted weekly. Their goal is to illustrate and consolidate the theory through practical exercises. Their detailed solution is distributed a week later on the course website. However, students are highly encouraged to actively solve the problem sets on their own as it is the best way to learn the material. 
In order to ensure sufficient interaction between students and instructors, an informal face-to-face discussion is organized during the official lecture time. This discussion is divided into two consecutive parts. First, the students can ask questions about the theory so as to clarify points regarding the podcast of the previous week. Then, the assistant is available to discuss the problem sets posted the week before. This informal discussion is not mandatory, but students are strongly encouraged to actively participate so as to stay up-to-date with the course material. The duration of this discussion depends on the questions and participation of the students and will vary from week to week. Nonetheless, sufficient time should remain for watching the following podcast during the lecture time. 
Depending on social distancing requirements, the class might be split into two groups that alternatively every second week take part in person in the informal discussion. The other group can participate in the discussion over lifesize.
Learning activities also include an integrated exercise by groups of 3 or 4 students. It consists in a one-time wind tunnel laboratory session, where aerodynamic forces are measured on a wing model, and a theoretical part, where the potential flow and boundary layer theories have to be applied to a wing. Results should then be summarized in a written report. This integrated exercise allows the application of the theory seen in class to a concrete case and the comparison between theoretical, numerical and experimental results.
The report of the integrated exercise is graded. Moreover, the participation in the laboratory is mandatory. Students who have not taken part in the laboratory will not be admitted to the exam.

Mode of delivery (face to face, distance learning, hybrid learning)

The course is offered as distance-learning. Podcasts and slides of the lectures are posted weekly on the course website. 
Exercises are done by the students on their own. The problem sets, and their detailed solution a week later, are posted on the course website.
The informal discussion about the theory and the exercises is organized face-to-face and over videoconference for the THRUST students. 

Organisational adjustments related to the current health context

Online written exam (January 12).

Recommended or required readings

The mandatory reference book is:

• "Fundamentals of Aerodynamics", John Anderson Jr., 5th edition, McGraw and Hill, ISBN 978-0-07-339810-5

Assessment methods and criteria

Below you will find information on the evaluation methods planned for in-person and remote exams as well as those planned for hybrid sessions. Depending on how the health crisis evolves, the chosen method will be communicated to you no later than one month before the start of the exam session.

Any session :

- In-person

written exam ( open-ended questions )

- Remote

written exam

- If evaluation in "hybrid"

preferred in-person


Additional information:

The final grade is obtained from two contributions:

• Written exam (exercises and theory): 70%
• Integrated exercise in groups: 30% (based on a written report)

Work placement(s)

Organizational remarks

The course is jointly taught by Prof. Terrapon and Dr. Andrianne.
Students are expected to be present in the official lecture room for the first lecture. All organizational details about the course will be communicated face-to-face at that time. Depending on social distancing requirements, the class might be split into two groups.
All course material and podcasts are posted weekly on the course website. 

Contacts

Students are encouraged to actively interact with the instructors, also outside of the lectures. It is recommended to set up an appointment first. For questions regarding the exercise sessions and the laboratory, the students can also contact directly the assistant. 
It is expected that the students follow a few basic rules when communicating by email: 

• Indicate as subject "AERO0001: ...".
• Only use ULg addresses (xxx@student.uliege.be).
• Always address emails to both lecturers and not only to one.
• Follow the elementary rules of politeness.