Influence of non-Newtonian gelatinous fluids on bubble collapse dynamics

The present experimental work investigates bubble collapse in gelatins of different concentrations under various driving pressures. Air bubbles are produced in gelatins of distinct mixture ratios and positioned free from boundaries. Pressure impulses with different intensities generated by a shock tube serve to trigger the bubble collapse. The bubble deformation is visualized by a focused shadowgraph system and recorded as continuous images with a high-speed camera. Image processing is conducted to analyze bubble deformation and radius changes. Results indicate that increasing the gelatin concentration tends to weaken the bubble oscillation, with the minimum radius ratio enlarged and the normalized collapse time elongated. Anisotropic bubble deformation appears and is enhanced in dense gelatins. In addition, higher driving pressures result in more rapid and intense bubble oscillations for all gelatin concentrations. By increasing the driving pressure the difference in the collapse time between different gelatins is reduced, but the trend is opposite for the minimum radius.     «

The present experimental work investigates bubble collapse in gelatins of different concentrations under various driving pressures. Air bubbles are produced in gelatins of distinct mixture ratios and positioned free from boundaries. Pressure impulses with different intensities generated by a shock tube serve to trigger the bubble collapse. The bubble deformation is visualized by a focused shadowgraph system and recorded as continuous images with a high-speed camera. Image processing is conducted...     »