Leicester Aerospace Engineering goes supersonic

The Department of Engineering, University of Leicester, has re-instated a closed-loop supersonic wind tunnel at its gas dynamics laboratory. The tunnel, which had laid in storage over several years, was refurbished and brought back to operational state by BEng final year project student Milan Dodia. The restoration was supervised by Dr. Aldo Rona, Thermofluids research group.

The tunnel is driven by a 70bar high pressure air supply via storage tanks and a two-stage compressor. It can test transonic and supersonic aerofoils as well as small models at speeds up to Mach 1.8 (540m/s, 1200 mph). Figure 1 shows the tunnel test run at Mach 1.4 with a diamond shaped aerofoil, a classic textbook supersonic profile. The schlieren flow visualization shows the leading and trailing edge shockwaves (the flow runs from right to left).

Milan commented ‘At the start of the project, I was both excited and anxious about building a supersonic wind tunnel. I had done nothing like this before. The tunnel components were in a poor state and there was little information on how they fitted and worked together. It took some effort to recondition all parts and I was very pleased with seeing the tunnel running at Mach 1.4 and Mach 1.8’.

‘I look forward to my next job interview where I hope to get an edge on candidates from other universities by possibly being the only applicant who has built and tested a supersonic tunnel as part of his degree.’

Dr. Rona commented ‘It is very satisfying to have one of the few operational supersonic wind tunnels accessible to university students at Leicester. Our Aerospace Engineering degree programme has attracted good quality students who are keen to develop a first-hand experience in compressible flows. Our supersonic Plint tunnel has no moving part to drive the flow and uses a simple white light source, similar to a car headlamp, to visualize the flow. This makes its operation accessible to undergraduates.’

‘I would like to acknowledge the support given to Milan by the engineering technical staff, in particular, by Mr. Dipak Raval, Julian Jones, and Paul Williams.’

The Plint supersonic wind tunnel is able to test a range of small models in rarefied air. It may be of interest for the study of lifting body concepts for the exploration of other planets as well as to study compressible flow components such as gas regulators and butterfly valves.

More images of the Plint tunnel and of the shockwaves at the higher speed of Mach 1.8 are available on the project website.

Figure 1: Schlieren visualization of a diamond-shaped aerofoil at Mach 1.4.