Summary
The qualitative study of the interaction between planar shock wave and a hemi-sphere-cylinder model with and without corona discharge plasma from its copper head have been done in the shock tube facility of Institute of Aeronautics and Astronautics in National Cheng-Kung University. With the incident Mach number of 1.3-1.69, the shock wave reflected on the model with regular reflection and transition to Mach reflection have been observed for model without corona discharge plasma. With the corona discharge plasma effect from the model copper head, the similar shock wave patterns were observed. However, a widening thickness of the shock and a shortening of the length of the Mach stem were observed and the location of the triple point is closed to the model surface. The curvature of the reflected shock wave is being increased. From the measured pressure signal of the relative strength of the shock reflection from the model head, a longer time is need and the measured signal strength is much smaller. It has clearly shown that under the effect of corona discharge plasma the shock reflection from the model head with a smaller speed and a much weaker strength. This is a strong indication that the corona discharge plasma can decrease the strength of shock wave properly.