Experimental investigation of viscous effects upon a breakup of droplets in high-speed air flow

The deformation and disintegration of water and silicone oil droplets were investigated experimentally in a shock tube. Optical visualization was performed by means of the shadowgraph method. Droplets with diameters in the range of 200 to 500 m were generated by an oscillating capillary. The smallest Weber number in the present experiments is close to the critical value of the breakup. The droplets disintegrated in the stamen or bag mode for moderate values of the Weber number. The effect of the viscosity of the liquid on the breakup mode and the breakup time is discussed.