Experimental study of bubble rupture during shock-fluid interaction

Head injuries are associated with exposure to high energy explosive detonation. There are four distinct types of blast induced neurotrauma (BINT): 1) these caused by supersonic shock waves propagating in the atmosphere (primary), 2) high velocity impact of shrapnel and debris (secondary) 3) acceleration and deceleration of the body and collision with the solid objects in the field (tertiary) and 4) exposure to high temperature and toxic gases (quaternary). One of the mechanisms implicated in non-impact primary blast-induced traumatic brain injury (bTBI) is cavitation. It is hypothesized that cavitation can occur in the cerebrospinal fluid (CSF) layer, brain interstitial fluid, and possibly also in the cerebral blood. In this thesis, it is tested that if a bubble is present, it collapses when a shock wave passes through it. The effect of shock waves on cavitation is simulated using a fluid filled cylinder made of polycarbonate. This simplified model represents the idealized skull-brain complex and was subjected to blast with the Friedlander waveform type of loading. Bubbles are introduced in the fluid filled cylinder in a controlled manner and the behavior of these bubbles during the blast is studied using fluids with different properties at two discrete shock wave intensities. It is found that the bubbles collapse under shock loading and partially regroup after the passage of the shock. The frequency of pressure wave in the fluid is altered during the collapse and regrouping