Sometimes when you look back at your career, you begin to wonder how far you have come, solely driven by the seeds of inspiration sown in your mind.

Karthick SK, our next pathbreaker, Fine Postdoctoral Fellow & Aerodynamicist, tries to understand the behavior of fluids flowing through ducts at different speed regimes, especially in supersonic air intakes, combustion chamber of a gas turbine, or the exhaust of a jet nozzle.

Karthick talks to Shyam Krishnamurthy  from The Interview Portal about visiting Naval Airbases near his hometown and witnessing from close quarters,  the mammoth fighter aircrafts and jets taking-off into the sky from the runways.

For students, dont just be awe-struck by supersonic jets, be a part of cutting edge innovations that will enable a stable, cheaper, and efficient means of supersonic transport around the globe in the future.

Hi Karthick, tell us about your background

I was born in Kanchipuram as the first child, and I have a younger sister who also has a Doctorate in Architecture. My father is a retired Professor in a polytechnic college. My mother is a former Principal of a matriculation school. Both of them are outstanding teachers, and they inspired us a lot. Being born into an educated family, my early life was seeded with plenty of learning opportunities and exposure to the outside world.

During my childhood days, I developed an interest in drawing and writing from my mother, who used to draw sketches of plants and animals for her Master’s studies in Biology. I started to operate computers at the age of eight since my father had a computer for his design projects. I spent most of my childhood inside the house in my sister’s company due to low immunity and health issues. 

My high-school provided me a great platform to cultivate my co-curricular skills. I did my schooling at Anderson Higher Secondary School in my hometown, which was a game-changer. Seeing my potential, my school helped me win three state awards, many regional & district awards on various science quizzes and essay writing, especially in my mother tongue (Tamil) and occasionally in English. Although I am a Researcher now, my creative skills that were inculcated in my childhood are still growing, thanks to my school.

The collection of my creative scribbles from my high school were later published as a poetry book, titled ‘Poo Maalayil Oru Malligai.’ It also pushed me to write more stories and pen lyrics. In the near past, during my doctoral studies, I had also served as an Editor and released a Tamil literary book called ‘Minnal-2018’ along with my dear wife.

Later on, my interest in photography pushed me to pursue independent film-making. Through a lot of hard work and learning experiences, I managed to form a team to pursue my dreams. I have successfully started a simple low-budget production house called ‘Virtual Studios’ and produced nine short films and directed three. My enthusiasm for film-making has laid another career track as an independent music producer. I have released many single-tracks so far. I am also actively encouraging and funding young talent to score independent albums under our banner.

What did you study?

I am currently a Fine Post-Doctoral Fellow at the Technion-Israel Institute of Technology, Haifa, Israel. I am continuing here as an Aerodynamicist (Researcher in the Aerodynamics Division) in the Technion-Wind Tunnel Complex from the Faculty of Aerospace Engineering under the guidance of Prof. J. Cohen. I have been in the Faculty for almost two and a half years now.

I got my under-graduation (UG) degree in the Department of Aeronautical Engineering from Rajalakshmi Engineering College, Chennai (2010). I finished my post-graduation (PG) in Aerodynamics of Ballistics, Missiles, and Rockets in the Department of Space Engineering & Rocketry from Birla Institute of Technology, Mesra (2012). 

I got my Doctorate in the Indian Institute of Science, Bangalore, from the Department of Aerospace Engineering (2017). I did my experimental fluid dynamics research in the Laboratory for Hypersonics and Shock-wave Research. I continued there for a few more months as a Research Associate until the middle of the next year (2018) before joining as a Post-Doctoral Fellow in Technion 

Tell us, how did you end up in such an offbeat, unconventional and cool career?

My father served in the National Cadet Corps (NCC) in the Naval wing for a long time. He always took me to the Naval Airbase station near our hometown (INS Rajali, Arakonam) during his NCC field camps. I witnessed from close quarters,  the mammoth aircrafts taking-off from the runways. I had also checked out many helicopters and fighter aircrafts with other cadets. The trainers used to explain the flight controls, and some of us were given the opportunities to try out a few controls on the grounded planes. 

On the other hand, my school teachers, especially my Headmaster, ensured that we had a substantial library to understand the real-world events. During his tenure, there was a big book exhibition organized, specifically for our school students at the time of ‘centenary year celebration of the first flight (1903-2003)’, where we had been introduced to the contributions of the former President of India, Dr. APJ Abdul Kalam and his inspiring book’ Wings of Fire.’ Needless to say, at the end of my schooling, I decided strongly to pursue a career in Aeronautical Engineering.

Based on the credentials I had possessed at the end of my higher secondary exams, I was admitted into Rajalakshmi Engineering College in the Department of Aeronautical Engineering. The course was relatively new to the college, and we were only the second batch. However, we never felt like we got stuck in the newly started under-graduate program. We had been blessed with many experienced Faculty members from eminent institutions like IITM, ISRO, and NAL. Our department had strong leadership and ensured that we got proper exposure to the field. My fluid dynamics professors (Prof V. Ramjee, Prof E. Rajakuperan, and Prof. Y. K. Sinha) arranged fantastic field trips to the Wind Tunnel Facilities available in the southern states of India, where we got an opportunity to visit the laboratories of SERC, IITM, ISRO, and IISc in successive semesters. During one of the visits, I met my doctoral thesis guides Prof. K. P. J. Reddy and Prof. G. Jagadeesh, who were delivering fascinating lectures to the public at that time. To be frank, that was the first time we came to know about the existence of the eminent institutions like IITM and IISc.

Later, at the end of my under-graduation course, my professors arranged a thought-provoking visit to the NAL (National Aerospace Laboratories) in Bengaluru, where we attended a ‘Flow Visualization’ symposium. I met great minds there and witnessed curious aerodynamics research projects. As a continuation, we had been taken to the labs in IISc-Bengaluru, where we saw something that still amazes me whenever I think about it. We had been asked to witness the wind tunnel experiments carried out in a few of the laboratories. One researcher (Mr. V. Surendranath) took us into a vast room and started explaining about the facilities. He said that they test scaled flight models in the wind-tunnel. We looked around, and we could not see any wind-tunnels lying around similar to the one we saw in our textbook. For us, the place looks like a vast dark cinema theater. We thought that they would put a video presentation in that big dark hall.

We innocently asked him where the wind tunnel was, and he politely replied by saying that we are standing inside one of the tunnels. We were stunned, and honestly, there were no words to express our surprise. We were standing in the air-intake section of India’s one of the largest wind tunnels, and the test-section (of 14 ft by 9 ft cross-section) was near us. It was so big, we thought it was a theater or auditorium. In the test-section, there was a scaled model of Light Combat Aircraft (LCA) Tejas (by HAL) mounted on the struts and getting ready to be tested. We touched and felt the modeling aspects of LCA Tejas and took notes on the instrumentation. We even watched a portion of the required dataset being acquired at subsonic speeds. The memory is so vivid, and I will cherish it till my last breath. 

Tell us about your career path

I realized that my under-graduation knowledge may not be sufficient to pursue a research career in Aeronautics, and I was determined to do post-graduation studies. I was not exposed to the advanced entrance examinations available at that time. However, through the inputs from my teachers, I appeared for GATE exams and scored decently. My batchmates were talented, and few of us even secured University Ranks. With those two accolades in our quiver, some of us joined Birla Institute of Technology – Mesra for our Master’s studies in Space Engineering and Rocketry. My GATE score helped me to fetch a scholarship to support my studies at BIT. 

Unlike other places where graduate studies are dominated with regular classes and a mini-thesis at the end, we were immediately asked to work on our Master’s thesis from day one. Our department had a brief history in providing foundational technologies for Rocket & Missile research in India, as the division operates closely with ISRO. We had enough facilities and had been offered big research projects and funds to begin our work. We kept ourselves busy and learned a lot from the experienced faculties (especially Prof. J. K. Prasad, Prof. S. Das, and Prof. P. Kumar). The research environment and my professors motivated me strongly to do doctoral studies in Aerospace Engineering. Later, during one of the guest lectures in my department, I encountered a fascinating speech delivered by my Ph.D. thesis supervisors. That lecture session sealed my fate. I told my PG supervisor that I would like to work in the labs of IISc, especially under Prof. Reddy or Prof. Jagadeesh. He offered me the necessary counsel and guided me towards applying for a Ph.D. position in IISc.

I got selected to pursue doctoral studies in IISc-Aerospace Engineering. I had been offered a Fellowship to complete my doctoral research. IISc is a spectacular place to learn and to do research. I am so thankful to my supervisors, my seniors, and my colleagues, who made me feel at home. Like in my graduate studies, my doctoral lab was filled with multi-talented personalities from whom I have learned a lot. After a brief period of research and interactions with many, I realized the need to go to other countries and understand their research methodologies. Once I finished my thesis, my professors and my seniors motivated me enormously to find a post-doctoral research position in other countries, having a strong aerospace research program. Later, I applied to Prof. Cohen under whom my PG professor (Prof. Das) had finished his post-doctoral studies. I got the position with a Fellowship, and presently, I am here, living my dream. 

What was your research in IISc ?

During my doctoral research, I continued the research work of my dear senior (Dr. Srisha M. V. Rao). We worked towards understanding the flow physics of a supersonic jet flowing through a confined passage. Supersonic jets can be seen in a fighter jet or space shuttle engines’ exhaust plume during take-off. Upon enclosing the jet within a solid wall, the jet’s thermal signature could be altered and could be exploited towards stealth applications. Initially, I had reservations about continuing an existing research statement. However, it turned out to be a great learning opportunity for me, as my senior shared a lot of his research expertise with me in a short amount of time, and we ended up studying the problem together. A few years later, we won the best poster award for our presentation at an international conference held in Israel (2015). It made me realize that we are progressing in our field, and I felt delighted in particular that my peers consider our approaches/findings research worthy. I am still thankful to my professors, seniors, and my department for providing an excellent opportunity to fly to another country and present my findings.  

Tell us about some of the challenges you faced in your career

I was from a rural area, and I studied in a simple government-aided Christian school. I never even had a chance to interact with students from big-city schools studying the central board syllabus. I was not used to fluent English communication and did not have a lot of confidence. My interactions and success were extremely limited to my hometown and only among the other state-board school students. When I got a position in my UG college to pursue my engineering studies, I felt utterly isolated and thrown out of my comfort zone. I still remember my first day on the urban campus so vividly. For a few months, I felt really alone and tried to cope with the changes around me. I gradually started to learn the ways around and started communicating with my colleagues. I gathered confidence and asked whatever doubts I had with little English that I knew, to my professors. My professors began to notice something in me and monitored me closely. It all came to the engineering chemistry class test. After the exams, my professor came with the evaluated scripts in the next class. He started distributing the sheets based on scores in an ascending order. Unusually, he did not tease anyone; instead, he gave useful pointers to everyone while distributing the transcripts. Apparently, the procedure revealed the scores to all. 

Time passed, and my name was not called. I was a little puzzled that my name was not called earlier. It all came down to the last paper which had the highest score. He called out my name. He said that I had secured full marks. I was surprised. The class was shocked. He was having mixed feelings. He continued saying that my paper was peculiar. He noted that it was utterly similar to the textbook word by word. He told everyone that I got full marks but just by memorizing the entire text. He appreciated me for the marks, and his intention was not to embarrass me in front of my class. However, he gave a handy piece of advice. In school, we had memorized, mostly. Exams were frequent, and we could not pester teachers or torture ourselves with questions like “why”. I studied in a classroom where there were 120 students enrolled. My teachers did what they could do at their best. The easiest solution was to memorize. It was quick and proven to be useful to secure ranks. However, in engineering, it was a different ball game. My engineering chemistry faculty told me that engineering is about understanding the concept and urged me to portray my understandings in my own words. I was under his radar, and I tried to follow his words faithfully. It became straightforward in later days, and that was a great challenge to overcome. However, such a transformation is mandatory for every student, perhaps in school itself. Memorizing and repeating will not do any good for anyone.

Mathematics is the language to understand the physics around you. Without it, you cannot engineer a problem and come up with a tangible solution. Due to my ignorance and the way I had studied, engineering mathematics was always a challenge. Not that I had not scored well during my UG studies, but the underlying principle behind every math-step was difficult to understand for me. I learned only simple shortcuts and brute steps to arrive at answers that were convenient in answering the trademark questions still asked in school/university question papers. The beauty of the mathematical language was only revealed to me only when I came to IISc, where everything is math. I felt so overwhelmed and too stressed. I tried to avoid any theoretical or mathematical subjects. I could not converge to a particular research topic that did not involve math. I felt so insecure and unwanted on the campus. My department offered me the necessary counseling to help me figure out a comfortable topic where I can mutually progress in the thesis title and understand the math involved at my own pace. I exposed myself to further challenges involving complicated math and tried to learn it properly. I managed to succeed and finish everything in the stipulated time. Of course, my subject instructors’ additional care, the unprecedented support of my supervisors, and the constant motivation from my colleagues helped me rise above my fear.

From my childhood, I cannot distinguish left from right and a positive sign from a negative sign (Gerstmann Syndrome). I can write scripts in a mirrored fashion flawlessly at a regular speed in both Tamil and English. Under stress, or even at ordinary times, I will keep inversely uttering things. I never felt it as an issue as it has never affected me in a big way except while making some careless mistakes here and there. However, I realized that I could not argue or explain my perspective to others with clarity under heat. Once I arrived for my post-doctoral studies, where non-native English speakers are large in number, many had told me that I was hard to understand. It was tough for me, especially talking to my supervisors. Research meetings were a routine, and they had been very stressful. Everybody sticks with a strict schedule, and explaining things to the point without creating confusion or wasting time is very important. I had many frustrating meetings and felt sad. Later, with my advisor and friends’ help, I am still trying my best to articulate better in a scientific language. I have always wanted to be a Professor. But under stress, I watched myself crumble. Thankfully, I am recovering, and I am persistent in achieving my goal. No amount of stage speech and interactions with your colleagues will prepare you for these kinds of events. These are all just the byproducts of evolving in a closed society. The actual world is really raw, brute, and mostly blunt. We will face it, recover and rise above it. 

Tell us about the current research you are working on at Israel

Presently, I am concentrating on investigating the flow kinematics of internal flows. In simple words, I am trying to understand the behavior of fluids while flowing through ducts at different speed regimes, which is unknown, especially in complicated passages like the supersonic air intake, combustion chamber of a gas turbine, and the exhaust of a jet nozzle. I use advanced optical diagnostics like lasers as the light source to illuminate particles as tracers to monitor fluid packets’ motion. This motion gets complicated if the fluid behaves chaotically, like in the turbulent flow, which is everywhere. Coming up with a mathematical model to explain and predict some of the primary flow features of an unsteady flow field like the flying bodies of different shapes at different velocities are the primary objectives. 

What are the required skills?

To be an aerodynamicist or an engineer, the essential requirement is to have excellent analytical skills and express it in layman terms. Analytical skills can be cultivated by learning rigorous mathematics logically (not in a brute force manner – our current education system is rigged in that way). Expression ability can be acquired if one could imagine, visualize, and articulate one’s ideas. Consider people who can quickly sketch a working principle of a device that they conceptualized in their minds. They are the people who should be in engineering. Nowadays, learning to draw digitally is an easy skill to acquire. People know modeling software like Illustrator, AutoCad, Catia, Solidworks, etc. in weeks. However, analytical skills require schooling and thorough practice of the respective discipline. Assignments, homework, and projects are meant to acquire such analytical skills, but somehow our generation finds an alternate by going through a solution manual or solved questions. Such behaviors pose a hindrance to developing analytical skills. 

When I started my undergrad coursework, I decided to learn CAD modeling software. I finished it in a few months, with the basics being covered. It helped me in many stages of my research career to convey my thought process, design, and execution to others. On the contrary, I am still learning analytical skills. In my everyday work, I am trying to understand the complex physical processes and articulate it in the language of mathematics. It is a continuous process for me. Exceptional students and fellows from good schools typically have such a talent, naturally. Schools/Universities from where you are coming matters at this point as you will be surrounded by excellent faculty. But that is not always the case. Self-driven people have acquired talent over a while through their hard work too. There is no single way or a direct recipe to get analytical skills. I hope that one day through hard work and understanding, I will also acquire it. 

What is a typical day like?

A well-defined flow problem will be in their hand for all aerodynamicists, especially in the research area. A list of experiments to find out the necessary flow quantities will be the top priority. Reasoning out the erratic behavior of the considered flow quantities and associate with the known flow physics will be a part of the research process. Some of the flow physics will be completely new, and your experiments might shed some information. Forming an analytical basis for such new physics will be the next task. Validation of the results from simpler analytical models with the simplified computations or the final experiments provides a closure to the problem. 

On a regular day, I work on parts on all these major tasks. I will be working alone on some problems, whereas I will be working along with my colleagues on a few other problems. Sometimes we plan the experiments or computations with the respective lab engineers or the associates. I will be having plenty of pre-scheduled meetings to address the research problems. Scheduling experiments or computational runs, extracting results, analyzing the outcomes, and defending your findings with your colleagues and supervisors is always interesting. At the end of each research phase, we summarize our findings and send it to some of the reputed peer-reviewed journals towards publishing. We also go to respective conferences in our field to present our most recent results.

What do you love about your job?

In day-to-day life, many events are unfolding in front of us. As a researcher, it gives me immense satisfaction to be a person who can understand the physics behind those events, at least to certain extents. The ideas that pop up in my mind whenever I want to control/replicate a physical process on different scales always make me feel alive. However, the Job does not fill you with joy, always. Pitfalls are expected. When you get stuck in a dead-end, it can be really frustrating. But life is not easy for anyone. So, I have learned to live with my share of success and sorrows.

What is the benefit of your research to society?

My current research on high-speed flows will help in arriving at a simpler technology for supersonic transport. We need to move around the globe as quickly as we require, like a high-speed train. Current transportation means are cheaper and safer but not time efficient. When it comes to defense, countermeasures to a ballistic threat is always a topic of interest. We need to prepare systems that can be deployed very quickly to neutralize our enemy threats. Many researchers and companies are working towards achieving a stable, cheaper, and efficient means of supersonic transport around the globe. You can hear the loud noise of an aircraft taking off on an airport runway. In supersonic transport, the velocity will be really high, and so will be the associated noise. I am working along with my colleagues to develop a solution where we can significantly reduce the resulting noise. 

We can always ignite the fuel-air mixture in our kitchen gas stoves at a lower velocity. However, those flames could be quickly extinguished when you blow air upon it. Consider the planes that are flying at higher speeds. The aerodynamics of internal flows should be cautiously studied to mix (air-fuel), ignite, and hold the flame for the consistent and continuous combustion process. I am presently working on the internal aerodynamics of such a mixing process. 

In supersonic flows, shocks are unavoidable. The thunderous sound you hear whenever a fighter aircraft goes supersonic or the noisy flow coming out of a compressor pressure tank upon leaks or a burst tire tube is all due to the shocks sitting in the flow and the associated sound generation. These shocks are incredibly unsteady, and control strategies are generally employed to minimize shock-fluid or shock-structure interactions. Part of my research is also in understanding the mechanics of such unstable shock interactions.

Tell us about your most memorable work  

If I have to pick one of my most memorable works, I have to choose the particular research I had done with Prof. Jagadeesh and Prof. Reddy. Seeding the clouds with liquid particles of sodium chloride and silver iodide in Karnataka to artificially induce rainfall was the best one. I remember the long ride I took with my professors and my colleague. It was a joint venture with the Aeronautical Development Agency (ADA). Practically a viability test to see if we can develop a delivery tool to spray the clouds with particles in an unmanned aerial vehicle. We went to the ADA’s airbase and inspected the unmanned aerial vehicle they had at their disposal. We took the specifications needed and designed a particle seeding chamber to be deployed in the field. Due to my graduation work, I did not see it through the end of the project. However, the groundwork we had done inspired me and made me happy. 

Similarly, I worked in one of my professors’ industrial projects alongside my seniors to shock the tea leaves to accelerate the withering process. We went to Koodalur tea estates, where a working model of shock-wave based tea leaves treatment facility was already available. I also tried to help them develop a nanoparticle pesticide sprayer to treat the tea leaves. Like the previous project, I could not see it through the end of the research as I was only partially involved, and I had a thesis to finish. Those moments are one to remember every time I feel blue. Those field exercises really motivated me to stay on the research track, and I am thankful to my professors, colleagues, and seniors for providing me the opportunity. 

Your advice to students?

Keep studying new things. Never shy away from mathematics, which is the language of science. Go on field trips as much as you can. Correlate what you learn and what you observe. Keep asking questions and strive hard to find answers. Find an inspiring Mentor and Advisor. Be in an environment surrounded by like minded people. Have a strong goal, and work hard till you achieve it. You will enjoy the process. That’s the gist.

My future plan 

I want to teach. There are many shortcomings in the present education system. I am both the beneficiary and the victim of that system. I want to rectify the flaws it has and help to boost its strength. I want to be in a place where I can be of use to the upcoming generations who dreamt of scoring big in science and engineering. I am also interested in continuing research. So, in summary, wherever I can do both research and teaching, irrespective of the institution brand or symbol of prestige, I would like to be there. Many teachers, including my parents, drastically inspire me, and I want to be one such teacher to someone curious to take a leap.