The phenomena of cylindrical converging shock waves reflection on a wedge are investigated in a converging shock tube. Based on the shock dynamics, a special converging shock tube is designed and constructed to convert a planar shock wave generated in a square shock tube with an initial shock Mach number of 1.21 into a cylindrical converging one (the converging angle is 15 degree and the shock tube height is 95 mm). In order to investigate the converging shock reflection phenomenon, wedges with different angles of inclination are set in the converging part. High-speed schlieren photography with a higher temporary resolution is adopted to observe the shock movement and reflection. In addition, the numerical method VAS2D is also used as a supplementary mean. In our work, three different wedges are used, and regular reflection, Mach reflection and the transition between them are all observed in the experiments and numerical simulations. According to the detachment criterion under a planar shock condition, a stronger shock corresponds to a smaller critical angle. As the converging shock moving forwards in the converging part, the shock strength is increasing and the contact angle between the converging shock and the wedge is decreasing. Both of these two factors will influence the shock reflection phenomenon. The results show that for one case in this work, the variation range of the contact angle is about 15 degree during the shock moving in the converging part. During this process, however, the variation range of the critical angle calculated based on the detachment criterion is less than 2 degree. The transition between the Mach reflection and regular reflection occurs when the contact angle intersects with the detachment angle and different values is expected for different shock strengths and different wedges. Compared with a planar shock reflection case, the variation of the shock strength and the effect of the boundary wall will result in more complex wave patterns.
