Abstract
A Gas mixture of Ar and Freon 12 was used to produce a transonic flow of Reynolds number of the order of 106 in a shock tube. The positions of the shock wave on a NACA 0012 were observed with the shadowgraph method adopting plastic optical fibers as light guides and compared with Cook's experiment performed by using air as the driven gas. The results show that the optical fibers can be used satisfactorily for the shadowgraph and the gas mixture of Ar and freon 12 is useful for obtaining the transonic flow in a shock tube whose proof pressure is relatively low.
