Overview of activities at the ISL hypersonic shock tunnels

Author(s):  
Patrick Gnemmi ◽  
Julio Srulijes ◽  
Friedrich Seiler
1992 ◽  
pp. 182-258 ◽  
Author(s):  
B. Esser ◽  
H. Grönig ◽  
H. Olivier

Author(s):  
Ruchi Thakur ◽  
G Jagadeesh

The shock stand-off distance for basic spherical models was investigated in the flow regime of 1–2 km/s, a range for which data are unavailable in the open literature. Experiments were conducted on two hypersonic shock tunnels, at five different enthalpy conditions and two types of test gas, and the bow shock was captured using schlieren flow visualization technique. These results were compared with existing empirical relations and a good match was observed. To further corroborate the results, a computational analysis of the same problem was carried out using an in-house computational fluid dynamics code, HiFUN (High Resolution Flow Solver on UNstructured meshes), and the results were again seen to match well with the experiments. The shock stand-off distance is an important parameter for the design of high-speed airplanes, and therefore a solid quantitative understanding of this parameter is vital for all flow regimes. This paper aims to fill in the gap by investigating one of those regimes where available data are currently missing.


2016 ◽  
Vol 120 (1229) ◽  
pp. 1123-1152 ◽  
Author(s):  
R. Sriram ◽  
G. Jagadeesh

ABSTRACTShock-tunnel experiments are carried out to study the strong interaction between an impinging shock wave and boundary layer on a flat plate, accompanied bylargeseparation 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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