A start-up founded by researchers from the Indian Institute of Science promises to bring cutting-edge aerospace research to engineering colleges. Super-Wave Technology Pvt. Ltd., a company incubated in IISc, aims to commercialise its patented invention - a miniature version of 'shock tube' and 'hypersonic shock tunnel'. Apart from this, the company also wants to explore socially relevant applications of shock waves - a thin region of extremely high temperature, defined by dramatic variations in pressure and density. Shock waves, commonly encountered by fast flying aircraft and missiles, are created when an object moves faster than sound.
The founders of Super-Wave Technology Pvt. Ltd., who also happen to be researchers at the IISc, have significantly shrunk what is called a 'hypersonic shock tunnel' – an instrument that can simulate hostile conditions faced by aeroplanes and missiles moving faster than sound. The new devices are called 'Reddy Shock Tube' and 'Reddy Shock Tunnel', in honour of their inventor Professor K P J Reddy, Department of Aerospace Engineering, IISc. Prof Reddy also founded the Laboratory for Hypersonic and Shockwave Research at IISc.
Hypersonic shock tunnels are indispensable tools in aerospace engineering research. However, they are quite long, with the smallest being 10 meter in length, while the longest stretching for more than hundred meters. However, the Reddy Shock Tube and Shock Tunnel are small enough to sit on a table top.
Hypersonics is the study of objects moving at a speed higher than Mach 5, i.e., five times the speed of sound. When an object moves so fast, it encounters a shock wave right in front it that also moves along with the object. Shock tubes recreate shock waves in laboratory environment and allow scientists to study them deeply. However, one of the major roadblocks to hypersonics research so far has been its accessibility: the bulky hypersonic shock tunnel set-up occupies a large area and incurs huge costs of fabrication and installation. Only elite institutions and premier research organizations can afford to install this for experiments.
“It was Prof. Reddy’s wish to see improvements in the field of hypersonic research in the country. He wished to install a shock tunnel in all the major engineering institutions. Once he realized that we could produce shock waves even in syringe-sized tubes, we worked to fabricate the Reddy Shock Tunnel. It is compact and allows basic hypersonic research to be conducted in educational institutions”, says Dr. Sudhiesh Kumar, one of the team members.
The Reddy Shock Tube consists of 2 sections - a 400 mm long driver tube with a manually operated piston, and a 600mm long driven tube. Both are of 30mm in diameter and separated by a piece of tracing paper acting as a diaphragm. A piston is pushed manually into the driver section, thereby forcing the air towards the diaphragm station. When enough pressure accumulates, the diaphragm ruptures to produce the shock wave in the driven tube. For the shock tunnel, a convergent-divergent nozzle is attached to the end of the driven tube opening in to a dump tank. This set-up produced a flow of Mach 6.5 velocity at the exit of the nozzle. Though the flow lasts only for less than 200 microseconds, it is good enough to conduct basic research on these high speed flows.
In India, Hypersonics as a research area is gaining importance. The hypersonic missile research wing of the Indo-Russian venture, Brahmos, is a prime example. But we still face a shortage of researchers in the field. “We need more people to come in to this field. Most engineering graduates have experience only in subsonic technologies since the engineering colleges can’t afford to install a hypersonic shock tunnel.” says Dr. Sudhiesh Kumar. The Reddy shock tunnel, developed by Super-Wave Technology, allows students to have hands-on experience with hypersonics and can help generate more interest in this field.
About the authors:
Dr. Chintoo Sudhiesh Kumar is a Project Manager at Super-Wave Technology Pvt. Ltd.
Prof. K. P. J. Reddy is a professor at the Department of Aerospace Engineering, IISc.
About the Paper:
The Paper was published in the Shock Waves journal. Below is the link to the paper.