diagnosis technique of boundary layer

This paper gives visualising and measuring results of the surface boundary layer transitions for two dimensional airfoil and three dimensional delta wing models using the surface hot film (HF) technique, the infrared image technique (IIT) and the liquid crystal technique (LCT) in same wind tunnel. The results detected the surface boundary layer transition positions by three techniques were excellent identical for two dimensional NACA-0012 airfoil model. The results detected for three dimensional 60°delta wing model showed that the surface hot film technique can give quantitative information of the surface boundary layer transition positions, both the infrared image and the liquid crystal techniques as using were affected by environmental conditions.At appropriate conditions they can also give quantitative information of the surface boundary layer transition position.