Study of Cylindrical Explosive Shock Waves at Air-Water Interface

This study numerically analyzes the characteristics of shock wave propagation and attenuation in different mediums of explosion near the air-water interface (free surface). This study discussed flow physics like shock wave propagation, reflection, transmission, and cavitation qualitatively and quantitatively. The numerical simulation is carried out with air, water, and TNT (Tri Nitro Toluene), which were modeled using the ideal gas, Mie-Gruneisen (shock), and Jones-Wilkins-Lee (JWL) equation of state, respectively. The Coupled Eulerian-Lagrangian model is employed. In an explosion above the air-water interface, the shock wave propagates and reaches the free surface. Due to the acoustic impedance of water, the incident shock wave reflects, and part of the shock wave is transmitted into the water. The acoustic impedance of water is much higher than that of air, so this free surface acts like a solid wall. On the other hand, in an explosion below the interface, the incident shock wave reaches the free surface and the shock wave reflects as an expansion wave, resulting in cavitation. In an explosion at the free surface, shock wave propagates in both air and water; the propagation and attenuation of shock wave were studied. Hence, the free surface near the medium of explosion plays a significant role in the characteristics of shock propagation and attenuation effects.