Planar shock wave sliding over a water layer

• Published in: Experiments in fluids 2016-08, Vol.57 (8), p.1-5, Article 125
• Main Authors: Rodriguez, V., Jourdan, G., Marty, A., Allou, A., Parisse, J.-D.
• Format: Article
• Language: English
• Subjects: Compression waves; Delay; Delay time; Dispersion (wave); Droplets; Engineering; Engineering Fluid Dynamics; Engineering Sciences; Engineering Thermodynamics; Flow distribution; Fluid- and Aerodynamics; Heat and Mass Transfer; Letter; Longitudinal waves; Mach number; Reactive fluid environment; Ripples; Shock waves; Sliding; Surface waves; Wave dispersion
• ISSN: 0723-4864; 1432-1114
• DOI: 10.1007/s00348-016-2217-6

In this work, we conduct experiments to study the interaction between a horizontal free water layer and a planar shock wave that is sliding over it. Experiments are performed at atmospheric pressure in a shock tube with a square cross section ( 200 × 200 mm 2 ) for depths of 10, 20, and 30 mm; a 1500-mm-long water layer; and two incident planar shock waves having Mach numbers of 1.11 and 1.43. We record the pressure histories and high-speed visualizations to study the flow patterns, surface waves, and spray layers behind the shock wave. We observe two different flow patterns with ripples formed at the air–water interface for the weaker shock wave and the dispersion of a droplet mist for the stronger shock wave. From the pressure signals, we extract the delay time between the arrival of the compression wave into water and the shock wave in air at the same location. We show that the delay time evolves with the distance traveled over the water layer, the depth of the water layer, and the Mach number of the shock wave.