The LTVG Facility

The 200mm x 300mm Low-Turbulence Variable Geometry (LTVG) Supersonic Wind Tunnel is equipped with Mach 2 and Mach 3 nozzles. The facility was designed to fulfill three specific objectives: l) Low turbulence levels in the flow upstream of the throat. The design of the entrance cone, settling chamber and contraction was based on the experience developed by Bushnell and Beck with in the design of "quiet" supersonic tunnels at NASA-Langley Research Center; 2) Studies of boundary layer relaxation following strong flow deflections. For example, with an upstream Mach number of 3, the boundary layer relaxation following a 24 degree compression corner can be studied up to 50 initial boundary layer thicknesses downstream of the interaction; 3) Generous optical access. The working sections are being modified to accept 24" diameter optical windows to permit wide-field flow visualization and the use of optical probes. The tunnel is connected to the ejector system so that back pressures as low as 0.5 psia are possible. Therefore the tunnel can be operated at very low Reynolds numbers to study transition and transition control at Mach numbers of 3 and 5, and at very high Reynolds numbers representative of flight Reynolds numbers (up to 10e8/m).