NOL Hypervelocity Wind Tunnel. Report No. 1: Aerodynamic Design

The NOL hypervelocity wind tunnel will provide a high Reynolds number turbulent flow simulation in the Mach number range 10 to 20. This facility, much needed for large-scale testing of hypersonic vehicles, is under construction and will be operational late in 1972. Supply pressures up to 40,000 psi will be maintained constant for 1 to 4 seconds during which stable, condensation-free flow conditions will prevail. Very high Reynolds numbers are obtained by operating with nitrogen at temperatures just sufficient to avoid test section condensation. The facility, which operates in a blowdown mode, has separate legs for the three design Mach numbers 10, 15, and 20. Each leg is fitted with its own storage heater, diaphragm assembly, contoured nozzle, and diffuser. The three legs share a common gas storage supply, test cell and model support system, and vacuum sphere. The report highlights the more significant considerations leading to the aerodynamic design of the facility and includes discussions of the need for the facility, the initial requirements imposed on its design, and brief descriptions of the layout and operation of the facility.