Trains of bubbles flowing through a microchannel get distorted by periodic expansions and constrictions. In these images, flow is from left to right, and the narrow point of the channel is about 250 microns across. In narrow regions, the front of the bubble tends to move faster, while in wider areas, the back of the bubble speeds up. This causes the distinctive shape changes we see. Microfluidic channels with these exaggerated shifts in geometry allow researchers to study the physics behind liquids and gases seeping through the interstitial gaps of a porous media, like when water and gases move through rock and soil. (Image and research credit: M. Sauzade and T. Cubaud)
Celebrating the physics of all that flows