Credits: 3

Semesters Offered

Fall 2017, Spring 2022, Spring 2023, Spring 2024

Learning Objectives

Course objectives
The course will provide an introduction to the fluid mechanics of flows at high Reynolds numbers,
which is important in many applications including the flow around airplanes, cars and ships; the
flow around wind or hydro power turbines; the flow in internal combustion and gas turbine engines;
atmospheric flows; and many other cases. These types of flows are characterized by an inviscid
external flow coupled with viscous and generally turbulent flow in thin boundary layers. The course
will provide an introduction to both aspects and will also include a more applied component where
students will use CFD software to analyze applied flows in mini-projects.

Topics covered
• Laminar boundary layers
• Statistical treatment of turbulence; governing equations for the mean flow and the turbulence.
• Turbulent boundary layers; the log-law; production, transport and dissipation of turbulence.
• Turbulence modeling.
• Vorticity, stream functions, velocity potentials.
• Inviscid external flow; potential flow; circulation.
• Lift, drag and moments of airfoils; drag polars.
• Separated flows.
• Order-of-magnitude reasoning to simplify equations.

Learning Objectives
Learn the basic fluid mechanics of external flows at high Reynolds numbers. Learn to interpret the
partial differential equations in fluid mechanics, and make the connection between the math and
observed flow patterns. Gain a basic understanding of turbulence, including its statistical treatment
and how it modifies the transport processes. Gain an understanding of potential flows, including
introductory airfoil theory. Learn to use a software package for computing these types of flows using
turbulence models.

Prerequisites
Students are assumed to have taken an introductory course in fluid mechanics (e.g., ENME331).
Students should also have a working knowledge of some programming language, e.g., Matlab,
Python, or similar. Students need not be expert programmers – but they do need a willingness
to take on challenging programming tasks (with help from the instructor and peers in the class, of
course).

Course format
The material will be covered during two lectures of 75 mins each per week.
There will be weekly homework, consisting of a written portion (deriving equations, etc) and a
computational portion where students use Matlab, Python, or similar to process realistic data sets
and solve simple equations. Students will also have to download and learn to use a freely available
CFD software package.

Evaluation
The homework will be graded on the basis of completion, not correctness. Two or three exams (that
may be take-home exams) will be given and graded on the basis of correctness. The final grade is
a combination of the homework/project credit (20%) and the exam scores (80%).
Collaboration is encouraged in this class. Having said that, every student must complete their own
homework by themselves (e.g., write their own computer code, produce their own plots, derive their
own equations, etc). In other words, students are allowed (and encouraged!) to work together
when figuring things out, and to ask each other questions etc, but must make sure that they do the
homework themselves without copying.
Internet resources that explain concepts (like Wikipedia and some Youtube videos) can be
excellent learning aides – they explain the same thing in different words which may help students’
understanding. These types of internet resources are absolutely allowed. However, internet resources
that provide solutions to problems are not allowed and are considered cheating.
The exams must be completed without any collaboration.