Experiment on gas flow field of large-caliber hypersonic balance gun in half-space

As one of the main methods to study the characteristics of an object, experiment is the main way to verify the correctness and reliability of numerical results. The hypersonic projectile near the ground launch involves many complex physical phenomena, so the ground surface has an important impact on the flight stability of the projectile and the structural characteristics of the gas flow field. In this paper, we carried out a whole process experiment of a hypersonic projectile from the bottom of the tube to the muzzle based on the 300 mm balance gun. The muzzle pressure and the initial velocity of the muzzle were monitored by the data acquisition system. We obtained the influence of the ground on the gas flow field of the hypersonic projectile through the overpressure data on the ground near the muzzle. Meanwhile, the dynamic characteristics of the launch process are recorded by high-speed photography. The experimental results show that the muzzle shock wave meets the ground, and the reflection phenomenon occurs, forming a wavefront with opposite directions of propagation. It makes the pressure in the lower half of the domain significantly higher than that in the upper half. By analyzing the experimental phenomena and experimental data, this paper shows the development characteristics of the projectile’s flow field, as well as the influence of the ground on the flow field and the motion stability of the projectile.