Abstract: The flow field related to the interior weapons bay of a combat aircraft is associated with strong unsteadiness effects in the transonic range. The perforated test section of a 2.4 m×2.4 m injection driven transonic wind tunnel, whose test section caliber is China’s only one larger than 2 m, is redesigned so as to obtain more accurate experimental data. Striving for the best design, attempts are made using computational fluid dynamics (CFD) analysis to evaluate and optimize the preliminary design project of a pilot wind tunnel. The boundary conditions of the perforated test section wall are validated by comparing with the experiment results at Mach number Ma_t=1.4, and then used for simulations of several projects. The current research reveales that the flow characteristics are greatly influenced by the entrance transition section and outlet transition section. The contraction and expansion of the entrance debase flow quality. The attitude of the injection flaps determines the size of the separation area. Then different models using different open-area ratios of perforated wall at entrance are investigated based on the numerical results. Desired flow quality is obtained when the transition section adoptes reasonable open-area ratios.

Key words: transonic wind tunnel, test section, perforation, numerical simulation, aerodynamic design