Influence of the diaphragm material at the entrance to the supersonic shock tube nozzle on the flow around a blunt body

The results of experiments on measuring pressure and heat flow near the critical point of a blunt body in experiments on a shock tube with a nozzle are presented. It is shown that fragments of the diaphragm at the nozzle inlet have a significant effect on the flow structure near the critical point of the model and distort the signals of pressure and heat flow sensors. A method has been proposed to significantly improve the quality of a high-speed flow by selecting the optimal material and thickness of the diaphragms at the entrance to the supersonic nozzle.