Hypersonic Research in the High Enthalpy Shock Tunnel Göttingen

Kurzfassung

The High Enthalpy Shock Tunnel Göttingen, HEG of the German Aerospace Center is a free piston driven shock tunnel, which was developed and constructed from 1989 - 1991. In a free piston driven shock tunnel, the conventional driver of a shock tunnel is replaced by a free piston driver. This concept was proposed by Prof. Ray Stalker and, therefore, the tunnels are also referred to as Stalker tubes. HEG was commissioned for use in 1991, at that time being the largest facility of its type worldwide. Since then it was extensively used in a large number of national and international space and hypersonic flight projects. The research activities which were always strongly linked with CFD investigations range from the calibration process of the facility and the study of basic aerodynamic configurations, which are well suited to investigate fundamental aspects of high enthalpy flows, to the investigation of complex entry, re-entry, hypersonic flight and integrated scramjet configurations. Originally, HEG was designed for the investigation of the influence of high temperature effects such as chemical and thermal relaxation on the aerothermodynamics of entry or re-entry space vehicles. In addition to the operation at high enthalpies (12 - 23 MJ/kg), the HEG operating range was continuously extended. One emphasis was to generate test section conditions which allow investigating the flow past hypersonic configurations at low altitude Mach 6 up to Mach 10 flight conditions at approximately 33 km altitude. These low enthalpy conditions cover the range of total specific enthalpies from 1.5 - 6 MJ/kg.selected research activities conducted in HEG during its 25 years of operation will be presented including fundamental studies to quantify the influence of high temperature effects on the external aerodynamics of re-entry vehicles , investigations of supersonic combustion ramjet (scramjet) flow paths and research related to the laminar to turbulent hypersonic boundary layer transition process and the possible damping of second mode instabilities by ultrasonically absorptive surface materials.