MODELING AND SIMULATION OF INTERACTIONS BETWEEN BLAST WAVES AND STRUCTURES FOR BLAST WAVE MITIGATION

Explosions occur in military conflicts as well as in various industrial applications. Air blast waves generated by large explosions move outward with high velocity, pressure and temperature. The blast waves not only incapacitate military and civilian personnel, but also damages buildings, vehicles, and other properties. Hence, there has been extensive research on how to mitigate blast wave effects. Understanding the interactions between blast waves and structures is a very important step in the development of devices for blast wave mitigation. The objective of this dissertation is to explore the complicated physical problem of blast waves impacting structures. The structures comprise flat, V-shaped and cone-shaped structures. The structures can be fixed or free-standing. It has been recognized that fluid structure interactions (FSI) between a blast wave and a free-standing structure reduces the blast loads exerted on the structure. The dynamic response of a free-standing plate subjected to a blast wave is numerically studied to investigate the effects of FSI in blast wave mitigation. This dissertation develops a 1-D model which includes the blast wave reflection from a free-standing plate, the plate motion and the shock wave induced in the back of the plate. The Euler equations for the flow fields in the front and in the back of the plate are solved using the Van Leer flux vector splitting scheme coupled with the monotone upstream-centered scheme for conservation laws (MUSCL) and Runge-Kutta scheme. The reflected pressure for normal reflection is larger than that for oblique and Mach stem reflections, which occur when there is an incident angle between the incident shock front and the reflecting surface. Hence, it is expected that reflected pressure decreases when a blast wave impacts a V-shaped or a cone-shaped structure. A 2-D numerical model of interactions between a blast wave and a V-shaped or a cone-shaped structure is developed. The model simulates the blast wave reflection from a V-shaped or a cone-shaped structure, the movement of the structure and the induced shock wave behind the structure. Elliptic grid generation and coordinate transformation are utilized to solve the flow fields in the irregular physical domain