The Indian Institute of Science (IISc), Bengaluru, paid rich tribute to late scientist and leader Professor Roddam Narasimha, with the Aerospace Engineering Department naming their 0.5-metre diameter enclosed free-jet hypersonic wind tunnel after him.
It is a fitting tribute as Prof Narasimha, among his many scientific achievements, was a pioneer of experimental hypersonics in India. It was his visionary work in the 1970s and 1980s that laid the foundation for the high-speed aerodynamics research work being carried out in the country today.
Naming the IISc facility after Prof Narasimha was an automatic choice among those in the aerospace department after he passed on 14 December 2020.
The name ‘Roddam Narasimha Hypersonic Wind Tunnel’ caught on quickly informally, according to Assistant Professor Duvvuri Subrahmanyam, but a formal naming ceremony had to wait until the world came out of Covid’s shadow.
The formality finally took place on Sunday (28 May) at the high-speed wind tunnel complex operated by the Turbulent Shear Flow Physics and Engineering Laboratory.
The chief guests were Dr Samir V Kamat, Secretary to the Department of Defence R&D and Chairman of the Defence Research and Development Organisation (DRDO), and S Somanath, Secretary to the Department of Space and Chairman of the Indian Space Research Organisation (ISRO).
Dr Kamat attended the event in person, while Somanath tuned in virtually, with a GSLV rocket launch from the Satish Dhawan Space Centre-Sriharikota Range (SDSC-SHAR) less than 24 hours away.
Besides distinguished scientists from the aerospace community, such as Dr Kota Harinarayana, who was behind the design, development, and delivery of the light combat aircraft (LCA), the august gathering on Sunday included Prof Narasimha’s wife and daughter, Dr Neelima Narasimha and Dr Maithreyi Narasimha, respectively.
A commemorative stone was unveiled mid-programme by Dr Kamat and Somanath (virtually) to mark the formal dedication of the wind tunnel to Prof Narasimha.
An aerospace scientist par excellence and a science institution builder in his own right, Prof Narasimha was instrumental in the development of aerospace technology in India, both at the technical and policy levels, throughout his long and illustrious career.
He received his education at the University College of Engineering and then IISc, and obtained his PhD at the California Institute of Technology in the United States, in 1961.
He went on to share a decades-long association with IISc that began as early as 1962.
During 1977-79, he was the Chief Project Coordinator at Hindustan Aeronautics Limited. From 1984 to 1993, he was Director of the National Aerospace Laboratories. He then served as Director of the National Institute of Advanced Studies, Bengaluru, from 1997 to 2004.
Thereafter, he became a professor at and founding chairman of the Engineering Mechanics Unit (2000-2014) at the Jawaharlal Nehru Centre for Advanced Scientific Research (JNCASR), Bengaluru. Towards the end of his career, he was the DST Year-of-Science Chair Professor at JNCASR.
From aerospace science and technology to atmospheric dynamics to computing, Prof Narasimha donned many a hat during his lifetime, not even necessarily limited to science alone.
His science advisory and mentorship are especially cherished by the aerospace community. His science policy roles include a place in Rajiv Gandhi’s Scientific Advisory Council, the National Security Advisory Board, and Manmohan Singh’s Scientific Advisory Committee.
He was the longest-serving member of the Space Commission, India’s premier space policy-making body, from 1989 through 2012, advising the top science and technology leadership of the country on various programmes, projects, and approaches.
For his outstanding work, he was honoured with the Padma Vibhushan, the second-highest civilian award in India, in 2013.
It would be fair to say that this brief account is merely scratching the surface of Prof Narasimha’s incredible life and work.
A wind tunnel is an enclosed space where the effects of high-speed air blasting past a scaled-down model of an object are investigated.
When a tunnel is “hypersonic,” it means that the air inside is zipping at a speed well over five times the speed of sound, estimated to be 343 metres per second and called, by convention, Mach 1. Thus, a hypersonic facility features speeds of over Mach 5 or 6.
The IISc today has and two hypersonic wind tunnels. Two other hypersonic wind tunnel facilities at ISRO and DRDO cap off India’s overall capability in this space.
The seeds of this work were sown decades ago, thanks to Prof Narasimha.
Addressing the audience on Sunday (28 May), Prof Joseph Mathew, Chairman of IISc’s Aerospace Engineering Department, recalled how Prof Narasimha had proposed a 0.2-m diameter free-jet hypersonic wind tunnel, to operate at Mach 8, as a pilot project in the 1970s — an extremely specialised facility posing a tremendous engineering challenge at a time of limited resources “and when India was in all kinds of trouble, on many fronts”.
The tunnel was sanctioned as an Aeronautics Research & Development Board (ARDB) project in 1976 and, after it was built, commissioned at IISc in 1985.
The 0.2-m tunnel was converted years later into a 0.3-m diameter tunnel. Thereafter, a new 0.5-m tunnel was proposed and the project to develop it was again sanctioned by ARDB. The new tunnel was commissioned in April 2014.
Both the tunnels today lie parallel under the roof of the high-speed wind tunnel complex.
The 0.3-m tunnel has assisted with as many as 35,000 blowdowns, 18 projects for ARDB, 80 for DRDO, and six for ISRO, and about 5,000 blowdowns for thesis work by students pursuing research work at the Master's and doctoral levels.
As for the Roddam Narasimha wind tunnel, “it has been quite active” since 2014 and “is expected to provide excellent service for both DRDO and ISRO and, perhaps, a lot more fundamental work will also get done,” according to Prof Mathew.
“This wind tunnel generates a circular air jet at hypersonic speeds, going up to Mach 10 (ten times the speed of sound). Test materials of various kinds can be placed in the jet to mimic hypersonic flight conditions,” the IISc while adding that “the facility is actively being used for multiple research projects.”
Speaking from experience, the ISRO Chairman, himself an IISc alumnus, said the hypersonic wind tunnel is “complex machinery.”
It was an “engineering challenge of very high magnitude” to get a 1-m hypersonic wind tunnel built at ISRO, he revealed.
This speaks to the accomplishment of IISc, as well as Prof Narasimha, in particular.
The ever-increasing reliance on computational methods and approaches might give the impression that facilities like wind tunnels are unnecessary.
The ISRO chief recalled how when they were building rockets some 10 years ago, the question of retiring wind tunnels came up often in discussions. Some even held the view that as computational capabilities grew stronger, testing facilities like wind tunnels would no longer be required.
But the space community is realising now, as they work on challenging problems like human spacecraft and the reusable launch vehicle, that testing subscale models and correlating the results with those from theoretical models remain an essential part of the process.
The added bonus of testing is that over time it helps even to plug the deficiencies that remain in computational capabilities.
Somanath said that despite the presence of testing facilities at NAL and ISRO, India remains dependent on organisations from countries like Russia, Canada, and Romania to carry out testing of its launch vehicles and various other machines.
“Even then, we are not able to meet most of our test requirements. It is such a huge demand. And we need to create facilities of this magnitude in our country. I think those actions which are being taken are really praiseworthy,” he said.
DRDO chief Dr Kamat said Professor Narasimha was, beyond being a scientist, a “true intellectual,” and that the agency has benefited tremendously from Prof Narasimha’s contribution to almost all of their programmes.
“We would not have been able to achieve what we have without his seminal contributions,” he said, crediting Prof Narasimha also for his leadership in turning NAL into a world-class laboratory.
“We need more scientists, more leaders like him to emerge,” he said.
“I think it’s time we start paying tribute to our scientists and intellectuals who have played a role in shaping science and technology in the country,” Dr Kamat said.
The DRDO Chairman related to Prime Minister Narendra Modi’s vision for India to become a developed country by 2047.
“We can become a developed country only if we become leaders in technology. Technology leadership can only happen if we remember our past leaders, use their memory, nurture new talent, and take risks,” he said, adding: “If we don’t take risks, we will always be followers.”
He stated that DRDO is working on hypersonic flight as well as cruise vehicles, as is ISRO. With several such programmes on the anvil, facilities such as this one at IISc are going to play a key role, despite the strides in computational fluid dynamics.
When he was director of National Aerospace Laboratories (NAL), Prof Narasimha presented a case for civil aviation in 1993, Prof Mathew recalled.
“Civil aviation will grow, and we should actively participate in this,” Prof Narasimha said at a time when civil aviation was yet to take off.
So farsighted was he that he wanted India to build aircraft themselves.
He had and promoted the first civil transport aircraft programme in the country, through a 14-passenger capacity multi-role aircraft.
Perhaps, more remarkably, Prof Narasimha was the one to the idea of a supersonic light combat aircraft (LCA) in India.
He was the chief investigator of the ‘LCA Studies’ project which was the start of it all, in the 1970s. At NAL, in the 1980s, he the development of carbon composite wings and flight control systems for the LCA.
Over the years, he provided the necessary guidance to the LCA programme. “He chaired many reviews in the evolution of LCA and provided critical inputs,” the Defence Ministry .
“I think he had an incredibly optimistic view of the future. And it is only if you have that kind of optimism will you think of a facility like this (the 0.3-m wind tunnel),” said Prof Mathew, adding that “Professor Narasimha didn’t merely have a vision. He chased it relentlessly.”
But it wasn’t all science alone with Prof Narasimha.
Prof G K Ananthasuresh, Dean, Division of Mechanical Sciences, highlighted how Prof Narasimha had an eye for the arts as well, and how he practised it alongside science.
As an example, he cited Prof Narasimha’s work from 1968 on the non-linear vibrations of a string. The fluid dynamicist had learnt to play the veena for four years. “It was his fascination with the veena that made him probe into the non-linear vibrations of a string,” Prof Ananthasuresh said.
Prof Narasimha was also fascinated by clouds. As a boy, he is said to have often looked up at the clouds in the sky. He came to be known, thus, as “Akasharaya”.
When he later delivered talks on clouds, he quoted profound poetry such as Kalidasa’s Ritusamhara, Prof Ananthasuresh recalled.
Clearly well-versed in physics, Prof Narasimha also exhibited an interest in metaphysics, as evidenced by his translation of the Sanskrit-language philosophical poem Yoga-Vasistha into English. The translated work was boldly titled Verses for the Brave: Selections from the Yoga-Vasistha.
Dedicating the wind tunnel to Prof Narasimha is “a classic case of standing on the shoulders of giants,” said Prof Subrahmanyam, who put the special Sunday event together with his aerospace team at IISc.
“It is because of the work done by Prof Narasimha and colleagues in the ‘70, ‘80s that now people of my generation are able to push forward and compete on a global scale,” he said.
“This is a very small tribute to Professor Narasimha that we can do by naming this tunnel in his honour. We are well aware that adding his name brings a lot of honour to this lab and this facility, but we think that is useful,” Prof Mathew said.
He added: “We want students and visitors who come here to see that name and, perhaps, ask why, you know, because in a little while, there will be people coming here who have not known Professor Narasimha. And then they may reflect and they may think of a vision for themselves and decide to do something to bring it to pass”.
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