Experimental Studies of Flow-Structure Interactions in Blast/Shock-Driven Complex Flows

Abstract

Blast waves, which are generated by the sudden energy release in a finite space, are encountered in various situations. As the blast/shock waves propagate, any object in its path can be damaged by the combination of significant compression behind the shock front and the subsequent complex flow-structure interactions. Insufficient protection from blast loads has led to a significant loss of human lives and enormous structural damage and economic loss, highlighting the importance of developing effective blast/shock mitigation technologies. However, due to the lack of fundamental knowledge in the flow-structure interactions in various blast/shock conditions, the conventional methods of mitigating blast/shock have relied on the brutal use of various cladding rigid/soft materials where the coupling between the flow and structures is usually ignored. Challenges remain in understanding the complex flow-structure interactions driven by the rapidly-evolving nonlinear blast/shock waves. In this thesis, a series of experiments were carried out in the East Carolina University Advanced Blast Wave Simulator (ECU-ABWS) to characterize the flow-structure interactions (particularly the flow-airfoil interactions) under various blast/shock conditions. While the incident (side-on) pressures at multiple locations along the blast propagation were measured by using a temporally-resolved multi-point pressure sensing system, the time-evolutions of blast-airfoil interactions were also qualitatively revealed by using a high-speed Schlieren imaging system. A high-accuracy force/moment measurement system was also developed and used to determine the aerodynamic responses of the airfoil structure under various blast conditions. The understanding of these interactions allows for the further development of more efficient blast/shock mitigation techniques.