Abstract: Low supersonic field in a wind tunnel can be realized by using its slotted test section and the air mass exhausted from the chamber. This article presents the results of a numerical simulation of the flow field about the transonic wind tunnel slotted test sections in order to achieve more accurate design which takes into consi-deration the numerous design parameters and complex flow mechanism of the slotted test sections. First, slotted test sections are designed according to general design rules. Four wall configurations and the air mass exhausted corresponding to different Mach numbers are presented. With the designed configurations, the characteristics of a low supersonic field are studied by numerical simulation when part of the gas in the plenum chamber is discharged. It is shown that a low supersonic field can be formed but it is affected clearly by the exhaust mass. Then, different models are investigated based on the numerical results. Such parameters as the position of the vent, wall thickness, the volume of the plenum chamber, and especially the slot open area ratios and slot cross section geometry all have an impact on airflow quality. Finally, the flow mechanism across the slotted sections is analyzed to show how the slot cross section geometry affects the uniformity of the test section flow field.

Key words: transonic wind tunnel, test section, slot, low supersonic, aerodynamics design