Autumn 2021
Prof. Vineeth Nair
Author: Vishnu Sankar
Pre-requisite courses: None
Pre-requisite skills: Basic coding skill in Python/MATLAB is useful
Course Content:
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Basic acoustic theory with an emphasis on the mathematical derivation from conservation laws. Acoustic behaviour in a closed pipe, open pipe, partially closed pipe, rectangular chamber, cylindrical chamber were studied which have relevance to a practical combustor.
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Methods capable of predicting unsteady motions inside a full-scale combustor were derived and studied, which was useful in studying the Linear stability of combustion dynamics.
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Models of Rijke tube, premixed flames, G-equation, diffusion flames, acoustic instabilities in solid rocket motors, vortex impingement models for combustion instability and other mechanisms driving combustion instability were studied thoroughly.
Coure Evaluation: Midsem - 15% Endsem - 30% Class Project - 40% Paper presentation - 10% Class Participation - 5%
Motivation behind taking the course: Being interested in fluid dynamics I always wanted to explore acoustics. This course was a sneak peek into the world of thermo-acoustics, which deals with modelling and predicting the instabilities inside a combustor due to the interaction between thermal and acoustic effects. The hands on course project and paper presentations were learning incentives to understand the practical applications.
Information about Projects/Assignments: The course project is an interesting and lengthy computational assignment which takes about 8-12 hours to solve. The concept used in the problem was well covered in the course. The professor refers a research paper which has the mathematical algorithm which needs to be coded out in MATLAB/Python. The code that one finally builds actually gives good results when compared with results from other research papers. This was the most interesting part in the course as it gave a practical application of the theoretical content that was learnt in the course. About 1 month was given to work on this problem.
Apart from the above project, there is also a paper presentation for about 15-20 mins. The professor sends a list of papers among which we need to choose one and present it to the class. About 10-15 days were given for making the presentation slides.
Overall Course Difficulty: 4/5
Average Time Commitment: About 2 hours/week
Attendance Policy: None
General funda: The exams can be little tricky, if not difficult. Don’t hesitate to reach out to the professor for practice questions. The professor gave us the endsem paper of 2017 year which helped us to understand what to expect from the exams.
Professor’s Teaching Style: The professor makes e-notes himself while taking the class. The pace was normal and his notes are very comprehensive and lucid enough. The contents are very organized. The course is mathematical in nature, if you are someone who loves FFT, eigen decomposition, you will mostly like the nature of the course. The physical emphasis was explained behind every mathematical step which made the overall course interesting. However the course gets hands on only in the last one month as all the fundamentals that were built in the first 2-3 months are necessary to even get started!
Who can take this course?: Anyone interested in Fluid mechanics or particularly in combustion driven acoustic instabilities in combustors can take this course. The combustion instability problem is an area of active research in modern aircraft combustors and anyone who has an interest in propulsion with a strong inclination towards fluid mechanics will enjoy this course.