Abstract: The operating efficiency of a compressor in the range of low Mach numbers at a supersonic wind tunnel test section (for which a considerable flow rate is required) is emphasized, and a design is provided in which pressure fluctuations can be reduced in a supersonic flow and also can be reduced in a supersonic wind tunnel circuit capable of operating at the required Mach number. Pressure fluctuations of flow brought about by inefficient operation can be reduced by operating an axial compressor 9 at a higher operating efficiency in the presence of a tunnel circuit resistor than the operating efficiency determined by the operating state theoretically calculated based on the Mach number required at a test section 19 in the absence of the tunnel circuit resistor. The Mach number at the test section can be made to conform to the required Mach number by causing the stream produced by the axial compressor 9 to pass through the tunnel circuit resistor such as a mesh plate 20 mounted in the tunnel circuit.

Abstract: The operating efficiency of a compressor in the range of low Mach numbers at a supersonic wind tunnel test section (for which a considerable flow rate is required) is emphasized, and a design is provided in which pressure fluctuations can be reduced in a supersonic flow and also can be reduced in a supersonic wind tunnel circuit capable of operating at the required Mach number. Pressure fluctuations of flow brought about by inefficient operation can be reduced by operating an axial compressor 9 at a higher operating efficiency in the presence of a tunnel circuit resistor than the operating efficiency determined by the operating state theoretically calculated based on the Mach number required at a test section 19 in the absence of the tunnel circuit resistor. The Mach number at the test section can be made to conform to the required Mach number by causing the stream produced by the axial compressor 9 to pass through the tunnel circuit resistor such as a mesh plate 20 mounted in the tunnel circuit.