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Mach 10-20 Longshot Hypersonic Gun Tunnel


The VKI Longshot gun tunnel is a reference short-duration hypersonic wind tunnel designed to simulate Earth and Martian atmospheric (re-)entries in a near perfect gas environment. It is used for aerothermodynamic investigations in the continuum regime requiring high Mach and extreme Reynolds numbers such as those experienced by orbital vehicles and space debris during their atmospheric flights. This unique worldwide facility is also used to address fundamental phenomena such as boundary layer laminar-to-turbulent transition, shock-boundary layer interactions, or viscous effects, among others. Given its perfect gas like environment, it is also an ideal wind tunnel for the validation of numerical codes. The facility finally benefits from advanced flow characterization techniques.

A high-velocity piston compresses the test gas to a pressure as high as 400MPa and a temperature of 2500K, corresponding to a specific total enthalpy of 3MJ/kg. This gas is then expanded through one of the following nozzles:

- a Mach 12 contoured nozzle (with an exit diameter of 426mm),

- a Mach 14 contoured nozzle (with an exit diameter of 541mm),

- a Mach 10 to 20 conical nozzle (with an exit diameter of 356 to 600mm).

Typical Reynolds numbers based on body length range anywhere up to 10x10^6. Useful test times are on the order of 20 to 80ms.

LongShot Scheme

Test articles are installed in the open-jet 15m3 test section using a high precision 6-axes positioning mechanism enabling any test configuration for pitch, roll, and yaw. Free-flight configurations are also commonly used.

  • Instrumentation techniques include:

    - 6-components balances for force/moment measurements (acceleration compensated),

    - thin-films and coaxial thermocouples for fast-response temperature/heat transfer measurements,

    - piezoresistive/piezoelectric pressure sensors for ultra-fast measurements (up to 1MHz),

    - flow visualization techniques (Shadowgraph/Schlieren/LIF-based Schlieren) coupled with a high-speed camera.

The data acquisition system includes high-precision amplifiers and offers a simultaneous sampling of 80 channels at 500kHz, + 16 channels at 2500kHz.

Following a major renovation in 2017, the wind-tunnel has been semi-automated. This improves the repeatability of the test conditions, and the efficiency of the investigations.


Space debris

“Aerodynamic characterization of space debris and determination of the associated total heat load in order to validate numerical simulations”

Intermediate eXperimental Vehicle (IXV)

“Experimental study on the efficiency of control surfaces, generation of an aerothermodynamic database”

Atmospheric Reentry Demonstrator (ARD)

“Wind tunnel heat flux and pressure measurements on the heat shield under laminar and turbulent boundary layer conditions”

Mars Sample Return Orbiter (MSRO)

“Heat flux measurements to support the development of the thermal protection system”

Hermes Spaceplane

“Generation of an aerothermodynamic database, investigation of control surfaces efficiency, and fundamental investigation of shock boundary layer interactions over compression corners”

Atmospheric Reentry Demonstrator ARD
IXV Intermediate Experimental Vehicle
Longshot Mach 12
Hemispherical debrisHemispherical debris
Longshot Ring 00 Mach 12
Longshot Ring 35 Mach 12
Longshot Ring 90 Mach 12
Annular debris - rocket interstage fairing

Dr. Guillaume Grossir
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Phone: +32 2 359 96 36