Blast wave absorption in liquid foams
Résumé
Due to their high apparent viscosity, liquid foams are good systems to absorb energy. This property is for instance used in the military domain to mitigate blast waves or explosions [Britan, 2009; Del Prete, 2013]. However, the underlying dissipation mechanisms are still not well understood. We address this issue by resolving in space and time a shock wave impacting a foam sample. We use a shock tube to send a shock wave on a foam with controlled liquid fraction, bubble size and physico-chemistry. The impacting shock creates an expanding cavity in the foam and propagates through the whole sample. The dynamics is recorded with a high speed camera and pressure signals are simultaneously measured. We show the influence of the bubble size on the attenuation of the pressure signal, the front velocity in the foam, and the size of the cavity. The roles of initial overpressure, liquid fraction and physico-chemistry will also be discussed.