Highly focused supersonic microjets: numerical simulations
  By focusing a laser pulse inside a capillary partially filled with liquid, a vapour bubble is created which emits a pressure wave. This pressure wave travels through the liquid and creates a fast, focused axisymmetric microjet when it is reflected at the meniscus. We numerically investigate the formation of this microjet using axisymmetric boundary-integral simulations, where we model the pressure wave as a pressure pulse applied on the bubble. We find a good agreement between the simulations and experimental results in terms of the time evolution of the jet and on all parameters that can be compared directly. We present a simple analytical model that accurately predicts the velocity of the jet after the pressure pulse and its maximum velocity. 
Ivo R. Peters, Yoshiyuki Tagawa, Nikolai Oudalov, Chao Sun, Andrea   Prosperetti, Detlef Lohse and Devaraj van der Meer
physics.flu-dyn