Talk on Enigma of Hypersonic Flight

Under the Science & Technology series, the VIF organised a talk on “Enigma of Hypersonic Flight” by Prof Gopalan Jagadeesh, Department of Aerospace Engineering, Indian Institute of Science (IISc), Bangalore on 14 March 2024. Prof Jagadeesh provided a broad overview of enigmatic nature of basic scientific, engineering and technological issues pertaining to hypersonic flight. He highlighted implications of hypersonic technology in commercial and military fields. He also highlighted the strategic nature of the technology, where the major power like the US, China and Russia are competing to have an edge over each other.

Moreover, Prof Jagadeesh outlined that the research in hypersonic technology can also lead to developments which would be very useful to help cure injured soldiers in the battlefield. Lt Gen RK Sawhney chaired the meeting. In his remarks, Lt Gen Sawhney emphasized the strategic significance of hypersonic technology to India and underscored the importance of new technologies to the government’s goal of making India a developed nation by 2047. Senior government officials, industry representatives, and members from the strategic community in addition to the VIF expert group members participated in the meeting.

The basic science is more like Brahma who is regarded as a creator. Today, we do not have many temples of Brahma, except one or two places including one in Rajasthan because nobody likes science. But science is the origin of all new ideas and without science, there will not be any engineering or technology. In science, we ask basic questions why and try to understand the basic nature to its full glory. Understanding outer nature is science, understanding the inner nature is spirituality. There is no confusion between these two. But in engineering, we have several avatars, including Zomato, Swiggy avatars. Engineers wear all kinds of hats.

In science, we ask the question ‘why’, and in engineering we ask the question ‘why not’. But nobody wants to understand how the technology works. However, the day technology is born, it is bound to die. Shiva is the creator and also the destroyer. New technology also feeds new science. The truth of infinite where science, engineering and technology actually become enigmatic in the area of hypersonic. In recent times, knowledge has become so important. Saraswati, the goddess of knowledge, has become critically important in the industry 5.0. From mass production, we are talking about mass customization today. This is actually the industry 5.0. People are no longer interested only in mass production, but they want mass customization.

In hypersonic, energetic interaction becomes very important. Hypersonic is actually going to be dominated by high energetic flow. It's not just about the speed. But hypersonic cruise system is very important because of the key parameters such as maneuverability; low flying ability; and ability to easily evade radar & early warning systems. It creates formidable task for interceptors. So hypersonic is all about speed, accuracy and non-detectability in the conventional sense.

Therefore, hypersonic technology is considered as the final frontier of aeronautics and astronautics. Hypersonic flows encountered by rockets, re-entry capsules and air breathing scramjet missiles are riddled with numerous complex yet intriguing phenomena such as shock-shock interaction, shock boundary layer interaction, non-equilibrium flows, shock material interaction, chemical kinetics etc. If the design and survivability of such vehicles can be ensured, applications ranging from low cost high speed transport, strategic advantage for defence and reusable launch vehicles can be made possible. It was noted that several efforts across the globe have been reported in the past to delve deep and decipher the flow physics of hypersonic flows pertaining to Scramjet engines.

However, despite meticulous efforts, there are several unsolved mysteries associated with such flows. The Laboratory for Hypersonics and Shock Wave Research (LHSR), Department of Aerospace Engineering, IISc, Bangalore and Centre of Excellence in Hypersonics (CEH), IISc, Bangalore have been in the forefront in furthering hypersonic research in India. Prof Jagadeesh was the founding chairman of the CEH in IISc, Bangalore which was started by the BrahMos Aerospace, New Delhi. He said that high lifting wave-rider configurations, 3-D shock wave boundary layer interactions, laminar to turbulent transition, start/unstart of scramjet intakes, supersonic combustion dynamics, ultra-high temperature ceramics coatings, robust navigation and guidance algorithms, multidisciplinary design optimization technologies are the major thrust areas being pursued at LHSR and CEH in IISc, Bangalore. It was observed that reliable ground testing, robust numerical studies, complimented with innovative flight tests will be the way forward towards realization of practical hypersonic flying systems. It was suggested that creating a National Directorate for Hypersonic, identifying mission mode projects, increasing funding for basic science, and improving synergy between all the stakeholders can help break the enigma of hypersonic flight and it will be a reality in the country.