For a low speed blow down wind tunnel with semi-open test section, the effectiveness of main flow damper in rapidly changing test velocity is verified through experimental research.

Damper: both gas flow regulating button and wind board are high grade PP material, connected with 304 stainless steel bar, manually adjust the outside valve knob, control air flow.

Mission Control answers the need with technologies such as shimmed damper performance, Dual Flow rebound, and detented adjusters.