To achieve a supersonic flow on the ground, a certain pressure ratio of upstream to downstream of the nozzle is required. Therefore, for supersonic wind tunnels, methods to blow air downstream with an upstream pressure of the nozzle increased or to forcibly exhaust a downstream pressure by a vacuum tank or an ejector with the upstream pressure increased, are widely used to obtain the pressure ratio required for achieving supersonic airflows.
To improve airflow characteristics in the test section, we execute design optimization for Laval nozzle using CFD (Computational Fluid Dynamics) to achieve the enhancement of airflow characteristics in the wind tunnel. The following figures show examples of CFD analysis results for nozzles of Mach number 2 and 4, respectively.
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| CFD results for a nozzle of Mach number 2 |
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| CFD results for a nozzle of Mach number 4 |
