Vortex formation in a shock-accelerated gas induced by particle seeding.

An instability forms in gas of constant density (air) with an initial nonuniform seeding of small particles or droplets as a planar shock wave passes through the two-phase medium. The seeding nonuniformity is produced by vertical injection of a slow-moving jet of air premixed with glycol droplets or smoke particles into the test section of a shock tube, with the plane of the shock parallel to the axis of the jet. After the shock passage, two counterrotating vortices form in the plane normal to that axis.

A novel dry powder inhaler: Effect of device design on dispersion performance.

The effect of device geometry and film characteristics on the performance of several passive flutter-induced dispersion DPI prototypes was investigated. Device resistance measurements indicated that the type of films, type of device geometry and specific device dimensions significantly affects the airflow resistance of the device. It was found that airflow resistance was positively correlated to the turbulence generated within the device.