Explorative Gradient Method-Based Research on the Optimization of Nozzle Flow-guiding Devices

Low-frequency buffeting is a common problem in automobile wind tunnels, it induces pulsations of pressure and velocity the test section. A 1:15 3/4 open-jet return-type scaled tunnel was used for this research, numerical simulations tests were implemented to study flow characteristics jet shear layer model tunnel. The results show that guide devices on inner wall nozzle can effectively reduce low-frequency buffeting, but presence deteriorated axial static gradient shape optimized through Explorative Gradient Method, carried out. An optimal ensure field uniformity Finally, reliability simulation practicability case verified hot wire microphone test.