Key technologies study of fluorescent mini-tuft application in the low speed wind tunnel tests

Fluorescent mini-tuft method is a surface flow visualization technology using mini-tuft with fluorescent material to visualize the flow characteristics under the UV light of specific wavelength.This method can reduce the disturbance of the tufts to the flow and give more accu-rate flow information.In this paper,the key technologies (including the making and sticking method of the mini-tufts,choosing the wavelength of UV lights and taking photos,etc.)of fluo-rescent mini-tuft method are investigated based on a high-lift device wind tunnel test of a certain civil aircraft in NF-3 low speed wind tunnel of NWPU.The results show that,(1)the flow pat-terns at different angles of attack are clear and intuitive,and the developments of the flow states with the angle of attack are shown,(2 )the flow state and range can be easily read in detail from the flow patterns,(3)compared with the fluorescent oil flow tests,the results are relatively sim-ilar under the same experimental conditions.It shows that the fluorescent mini-tuft method can exactly display the flow field.The flow visualization results agree well with the force measure-ment experiments and thus can interpret the force measurement results.