Research on flutter test technology of continuously adjusting dynamical pressure in high-speed wind tunnel

According to the defects shown in the flutter tests of stepped adjusting dynamical pressure in high speed intermittent wind tunnel,such as:long testing time,high gas consump-tion,and short acceptable life of testing models,researches on flutter test technology of continu-ously adjusting dynamical pressure in high-speed intermittent wind tunnels are conducted.Tech-nical problems of flutter test data processing and wind tunnel flow controlling have mainly been solved.The specific approaches are:in the 2.4m×2.4m blow off transonic wind tunnel,fixed Mach number and linear varying total pressure controlling strategies based on movement function are presented,and thus the flow controlling goal of fixed Mach number continuously adjusting dynamical pressure is achieved.The controlling uncertainty of Mach number reaches less than 0.005 without deviation of dynamical pressure.The Pick-Hold method is adopted to set up the subcritical prediction criterion in flutter boundary;according to the characteristic that the recipro-cal of predicting criterion is close to the normal distribution,a parameter estimation method based on the mathematical statistics theory can be used to reduce the diffusive sampling of the prediction criterion and then the accuracy of the subcritical prediction of flutter boundary can be increased.The results of wind tunnel verification test show that the flutter test results of contin-uously adjusting dynamical pressure is in consistent to that of stepped adjusting dynamical pres-sure,and the test technology has reached engineering practical levels;besides,the gas consump-tion is greatly reduced by using flutter test technology of continuously adjusting dynamical pres-sure,and thus it also has good economic benefits.