Work of Satish Dhawan at IISc made Tejas jet, missiles, Gaganyaan possible

Satish Dhawan pioneered development of wind tunnels in the country

satish dhawan A collage showing Satish Dhawan (ISRO) and an LCA Tejas in a wind tunnel (CSIR NAL)

Homi Bhabha, Vikram Sarabhai, Satish Dhawan. These three names are arguably the first ones that come to mind for many Indians when they think of pioneers of post-independence scientific research in the country.

Satish Dhawan was the third director of ISRO, serving in the role from 1972 to 1984. His tenure as ISRO chief was a time when the organisation, literally, soared, as an Indian-designed rocket made a successful maiden launch of an indigenous satellite in 1980.

Dhawan’s birth centenary is being celebrated on Friday. Dhawan, who died in 2002, was also the director of the Indian Institute of Science in Bengaluru for a record 19 years from 1962.There is a popular anecdote that Satish Dhawan accepted the offer from then prime minister Indira Gandhi to head ISRO on condition that he was allowed to remain head of IISc.

Dhawan, who held a PhD in aeronautics and mathematics from Caltech in the US, became director of the Indian Institute of Science at a remarkably young age of 42. Dhawan oversaw a massive expansion at IISc. When he took charge as director of IISc, there were 11 departments at IISc; by the time he left in 1981, there were 40, according to a post on IISc’s Connect blog.

Dhawan specialised in research into fluid dynamics, the study of the flow of liquids and gases, which has numerous applications in multiple fields.

In addition to Dhawan’s pioneering work as chief of ISRO, he is also credited with creating the first supersonic wind tunnel in India.

S.P. Govinda Raju, a retired IISc scientist, in a research paper, described wind tunnel as a “an aerodynamic test facility. It is mostly used to study flow patterns around bodies and measure aerodynamic forces on them. The bodies (called models) are usually scaled down but geometrically similar versions of bodies of interest like an airplane or an automobile. The results from wind tunnel tests can be 'scaled' to the actual velocity and actual body size using suitable scaling laws.”

Wind tunnels are, in simple terms, test facilities to finetune the design of any aerodynamic body to ensure it works as specified in the real world. It was under Dhawan’s stewardship that the first large-scale ‘open-circuit’ wind tunnel was opened at IISc in 1959. It was inaugurated by the then maharaja of Mysore. In 1973, India’s first hypersonic wind tunnel was opened at IISc, at a time when the country was ramping up development of its first space rockets and missiles.

The open-circuit wind tunnel was used to finetune the design of the Light Combat Aircraft Tejas fighter, long before it made its first flight in 2001. It has also been used to test the design of the Advanced Medium Combat Aircraft (AMCA), the country's first stealth aircraft, which is scheduled to fly around 2025.

In a 2017 article on IISc Connect, V. Surendranath, a senior scientist at IISc, described the work of the open-circuit wind tunnel. He said, “We have tested all sorts of objects: Chimneys, cooling towers, factories, launch vehicles, ships, and of course many aircraft. We have also provided our service to the LCA [Light Combat Aircraft], AMCA [Advanced Medium Combat Aircraft], ship development and other flight configurations."

The country's first hypersonic wind tunnel at IISc was used by DRDO to develop the Agni ballistic missile's design. The hypersonic test facilities at IISc have also been used to validate design of India's hypersonic missile efforts.

In March 2020, New Indian Express reported a new task for the 61-year-old open-circuit wind tunnel at IISc: Testing the design of Gaganyaan, ISRO's maiden manned space mission.

Surendranath told New Indian Express "each phase in the Gaganyaan mission will be tested separately to its maximum safety limit and the operational capability (of the rocket) will be proven”.

As Indians feel pride at the sight of a soaring ISRO rocket or a menacing missile from DRDO, it is only apt to remember the foundations that Satish Dhawan, and his colleagues, laid to make them possible.


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