# ME724 - Essentials of Turbulence

#### Instructor

Prof. Abhilash Chandy

#### Section

No sections, 80% of the class were M. Techs

#### Semester

Spring’20

#### Course Difficulty

On a scale of 1 to 5, I’d say 3. The course involved carrying out turbulent flow simulations for the course project which is something I had to learn. The content was easy to grasp if you follow the lecture and read the relevant text.

#### Time Commitment Required

The first half of the course was entirely theoretical and was easy to understand. So, a couple of hours per week were enough to be on track. The later content required simulations, so I had to put in more hours on learning how to do that.

#### Grading

The grading policy initially displayed was on an absolute scale, but we were assured that appropriate modifications will be made in the policy depending on the class performance. The grading at the end was super chill. Statistics: 20 AAs, 6 ABs out of 51

#### Attendence Policy

Attendance was not mandatory

#### Pre-requisites

- Undergraduate Fluid Mechanics (Compulsory)
- Engineering Mathematics (Compulsory)
- Ability to program, perform data analysis (Compulsory)
- Advanced Fluid Mechanics (Not compulsory, but desirable)
- Familiarity with probability theory, tensor algebra and constitutive equations (Not compulsory, but desirable)

#### Evaluation Scheme and Weightage

Initial Plan -

- Assignments (4) - 10%
- MidSem Exam - 40%
- Final Project
- Report - 30%
- Presentation - 20%

Modified Plan due to Lockdown -

- Top-up - 30% (everyone starts with this)
- Assignments (2) - 10% (another assignment for an extra 2%)
- MidSem Exam - 40%
- Final Project
- Report - 20%

#### Topics Covered in the Course

Fundamental Considerations, The nature of turbulence, Fundamentals of Turbulence (Equations of fluid motion and Statistical Description of turbulent flows), Scales of turbulent motion, Modeling and Simulation: Direct Numerical Simulation (DNS), Modeling and Simulation: Large eddy simulation (LES), Turbulent flow applications

#### Mechanism of Instruction and Teaching Style

The instructor showed a really amazing video in the first two lectures and explained a lot of concepts through that. After that, the slides were the primary teaching resource.

#### Assignments and projects in the Course

A basic tutorial on mathematics was set up which was just to refresh things. Assignments involved summarizing research papers, coding for finding the fast fourier transform of signals, etc. The project involved turbulent flow simulations and therefore required effort, but due to the pandemic, it was restricted to only a case-study of the different research approaches tried out for a particular problem setup. But learning how to do simulations in OpenFOAM or ANSYS Fluent is something which I really recommend doing if you’re interested in Fluids.

#### Exams

There was no endsem or quiz. The midsem paper was mostly mathematical and was very easy.

#### References

The ones suggested by professor -

- Turbulent Flows, Stephen B. Pope.
- A First Course in Turbulence, Tennekes and Lumley
- Turbulence: An introduction for scientists and engineers, P.A. Davidson

I majorly used the second reference (and parts of first).

#### Other Interesting Links

#### Importance of Course

Turbulence is an open research field even today. So, this course can provide you a very good overview of the field, and you’ll try out things on real life flow situations in your project, so that will help you learn a lot of important skills.

#### Motivation to take the course

I really liked the introductory Fluid Mechanics course (ME219) in my third semester and so, I was exploring related courses being offered in the spring. I also had the constraint of taking a course which did not involve heat transfer. When I first had a look at this course, I was immediately interested because I found a course which focused on one of the most interesting and mysterious aspects of Fluids.

#### How strongly would you recommend someone for taking this course?

Any who liked the course on basic Fluid Dynamics should definitely take the course.

#### When did you take this course? What will be the ideal semester to take this course? Any other course which can be done before this?:

I took it in my fourth semester (only 4 sophomores took the course). You can always take the course in your fourth semester, but if you want to try out hands-on simulation on simpler problems, you can take it in your 6th or 8th semester as well, after taking courses on Computational Fluid Dynamics (CFD).

*Review by:* Gagan Jain