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Shock-tunnel investigations on the evolution and morphology of shock-induced large separation bubbles

  • R. Sriram (a1) and G. Jagadeesh (a1)

Shock-tunnel experiments are carried out to study the strong interaction between an impinging shock wave and boundary layer on a flat plate, accompanied by large separation bubble with a length comparable to the distance of the location of shock impingement from the leading edge of the plate. For nominal freestream Mach numbers ranging from 6 to 8.5, moderate to high total enthalpies of 1.3MJ/kg to 6MJ/kg are simulated in the Indian Institute of Science's hypersonic shock tunnels HST-2 (a conventional Hypersonic Shock Tunnel) and Free Piston Shock Tunnel (FPST) with freestream Reynolds numbers ranging from 4 × 106/m to 0.3 × 106/m. The strong impinging shock is generated by a wedge (or shock generator) at an angle of 30.96° to the freestream. From the time-resolved Schlieren flow visualisations using a high-speed camera and surface pressure measurements on the flat plate using fast response sensors, a statistically steady flow field with a large separation bubble was established within the short test time of the shock tunnels (around 600µs in HST-2 and 300µs in FPST). The role of various parameters on the interaction – Mach number, location of shock impingement and flow total enthalpy – are investigated from the measured separation length and surface pressure distribution. For the nominal Mach number of 8.5, with shock impingement at 100mm from the leading edge, the separation length increased from 60mm to 70mm as the total enthalpy is increased from 1.6MJ/kg to 2.4MJ/kg; whereas it dropped drastically to 30-40mm at 6MJ/kg. This is due to the prominence of real gas effects at higher enthalpies.

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1.Delery, J. and Marvin, J.G. Shock-wave boundary layer interactions, AGARD-AG-280, 1986.
2.Gadd, G.E., Holder, D.W. and Regan, J.D.An experimental investigation of the interaction between shock waves and boundary layers, Proceedings of the Royal Society of London, Series A, 1954, 226, (1165), pp 227253.
3.Elfstrom, G.M.Turbulent hypersonic flow at a wedge-compression corner, J Fluid Mechanics, 1972, 53, (1), pp 113127.
4.Fay, J.G., and Sambamurthi, J. Laminar hypersonic flow over a compression corner using the HANA code, AIAA Pap. No. 92-2896, 1992.
5.Childs, M.E., Hijman, R. and Miller, D.S.Mach 8 to 22 studies of flow separations due to deflected control surfaces, AIAA J, 1964, 2, (2), pp 312321.
6.Hayakawa, K. and Squire, L.C.The effect of the upstream boundary layer state on the shock interaction at a compression corner, J Fluid Mechanics, 1982, 122, pp 369394.
7.Needham, D.A. and Stollery, J.L. Boundary layer separation in hypersonic flow, AIAA Pap. No. 66-455, 1966.
8.Coleman, G.T. and Stollery, J.L.Heat transfer from hypersonic turbulent flow at a wedge compression corner, J Fluid Mechanics, 1972, 56, (4), 741752.
9.Settles, G.S. and Bogdonoff, S.M.Scaling of two- and three dimensional shock/turbulent boundary-layer interactions at compression corners, AIAA J, 1982, 20, (6), pp 782789.
10.Humble, R.A., Elsinga, G.E., Scarano, F. and van Oudheusden, B.W.Three-dimensional instantaneous structure of a shock wave/turbulent boundary layer interaction, J Fluid Mechanics, 2009, 622, pp 3362.
11.Dupont, P., Haddad, C. and Debieve, J.F.Space time organization in a shock-induced separated boundary layer, J Fluid Mechanics, 2006, 559, pp 255277.
12.Garnier, E., Sagaut, P. and Deville, M.Large eddy simulation of shock boundary layer interaction, AIAA J, 2002, 40, (10), pp 19351944.
13.Wu, M. and Pino Martin, M.Analysis of shock motion in shock wave and turbulent boundary layer interaction using direct numerical simulation data, J Fluid Mechanics, 2008, 594, pp 7183.
14.Bray, K.N.C., Gadd, G.E. and Woodger, M. Some calculations by the Crocco-Lees and other methods of interactions between shock waves and laminar boundary layers, including effects of heat transfer and suction, ARC-C.P. No. 556, 1961.
15.Kubota, T.Lees, L. and Lewis, J.E.Experimental investigation of supersonic laminar, two-dimensional boundary-layer separation in a compression corner with and without cooling, AIAA J, 1968, 6, (1), pp 714.
16.Spaid, F.W. and Frishett, J.C.Incipient separation of a supersonic, turbulent boundary layer, including effects of heat-transfer, AIAA J, 1972, 10, (7), pp 915922.
17.Bleilebens, M. and Olivier, H.On the influence of elevated surface temperatures on hypersonic shock wave/boundary layer interaction at a heated ramp model, Shock Waves, 2006, 15, (5), pp 301312.
18.Delery, J. and Coet, M.-C. Experiments on shock wave/boundary layer interactions produced by two-dimensional ramps and three-dimensional obstacles, Workshop on Hypersonic Flows for Reentry Problems, 1990, Antibes, France.
19.Holden, M.S.Establishment time of laminar separated flows, AIAA J, 1971, 9, (11), pp 22962298.
20.Mallinson, S.G., Gai, S.L. and Mudford, N.R.Establishment of steady separated flow over a compression-corner in free-piston shock tunnel, Shock Waves, 1997, 7, (4), pp 249253.
21.Swantek, A.B. and Austin, J.M.Flowfield establishment in hypervelocity shock-wave/boundary-layer interactions, AIAA J, 2015, 53, (2), pp 311320.
22.Mallinson, S.G., Gai, S.L. and Mudford, N.R.The interaction of a shock wave with a laminar boundary layer at a compression corner in high-enthalpy flows including real gas effects, J Fluid Mechanics, 1997, 342, pp 135.
23.Davis, J.-P. and Sturtevant, B.Separation length in high-enthalpy shock/boundary layer interaction, Physics of Fluids, 2000, 12, (10), pp 26612687.
24.Mahapatra, D. and Jagadeesh, G.Studies on unsteady shock interactions near a generic scramjet inlet, AIAA J, 2009, 47, (9), pp 22232232.
25.Moss, J.N., O'Byrne, S., Deepak, N.R. and Gai, S.L. Simulations of hypersonic, high-enthalpy separated flow over a ‘tick’ configuration, AIP Conference Proceedings 2012, 1501, pp. 1453–1460.
26.Kumar, C.S. and Reddy, K.P.J.Experimental investigation of heat fluxes in the vicinity of protuberances on a flat plate at hypersonic speeds, J Heat Transfer, 2013, 135, (12), pp 121701:1–9.
27.Krek, R.M. and Jacobs, P.A. STN, shock tube and nozzle calculations for equilibrium air, Research Report No. 2/93, 1993, University of Queensland, Australia.
28.Sriram, R. Shock tunnel investigations on hypersonic impinging shock wave boundary layer interaction, PhD Dissertation, 2014, Indian Institute of Science, Bangalore, India.
29.Ram, S.N. Measurement of Static Pressure Over Bodies in Hypersonic Shock Tunnel using MEMS-Based Pressure Sensor Array, MSc (Eng) Dissertation, 2011, Dept of Aerospace Engineering, IISc, Bangalore, India.
30.Satheesh, K. The effect of energy deposition in hypersonic blunt body flow field, PhD Dissertation, 2007, Dept of Aerospace Engineering, IISc, Bangalore, India.
31.Moffat, R.J.Describing the uncertainties in experimental results, Experimental Thermal and Fluid Sci, 1988, 1, (1), pp 317.
32.Krishnan, L., Yao, Y., Sandham, N.D. and Roberts, G.T.On the response of shock-induced separation bubble to small amplitude disturbances, Modern Physics Letters, 2005, 19, (28–29), pp 1495–1498.
33.Chapman, D.R., Kuhen, D.M. and Larson, H.K. Investigation of separated flows in supersonic and subsonic streams with emphasis on the effect of transition, NACA TN-3869, 1957.
34.Sriram, R. and Jagadeesh, G.Shock tunnel experiments on control of shock induced large separation bubble using boundary layer bleed, Aerospace Sci and Tech, 2014, 36, pp 8793.
35.Simeonides, G.A. Laminar-turbulent transition correlations in supersonic/hypersonic flat plate flow, 24th International Congress of the Aeronautical Sciences, 2004.
36.Davies, W.R. and Bernstein, J.L., Heat transfer and transition to turbulence in the shock-induced boundary layer on a semi-infinite flat plate, J Fluid Mechanics, 1969, 36, (1), pp 87112.
37.Eckert, E.R.G.Engineering relations for friction and heat transfer to surfaces in high velocity flow, J Aeronautical Sciences, 1955, 22, (8), pp 585587.
38.Clemens, N.T. and Narayanaswamy, V.Low-frequency unsteadiness in shock wave/turbulent boundary layer interactions, Annual Review of Fluid Mechanics, 2014, 46, pp 469492.
39.Loth, E. and Matthys, M.W.Unsteady low Reynolds number shock boundary layer interactions, Physics of Fluids, 1955, 7, (5), pp 11421150.
40.Kulkarni, V. Investigation of flow modification techniques to reduce drag and heat transfer for large angle blunt cones in high enthalpy flows, PhD Dissertation, 2007, Indian Institute of Science, Bangalore, India.
41.Mohammed Ibrahim, S., Sriram, R. and Reddy, K.P.J.Experimental investigation of heat flux mitigation during Martian entry by coolant injection, J Spacecraft and Rockets, 2014, 51, (4), pp 13631368.
42.Furumoto, G.H., Zhong, X. and Skiba, J.C.Numerical studies of real gas effects on two-dimensional hypersonic shock wave/boundary layer interaction, Physics of Fluids, 1997, 9, (1), pp 191210.
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