ANATOMIC BUBBLES

Bubbles are familiar objects, yet their seemingly simple appearance conceals surprisingly rich fluid dynamics. As air inflates a soap bubble, the incoming flow generates a coherent internal circulation that evolves with the growing cavity. Looking inside, the motion bears a striking resemblance to the recirculating flow found within fluid-filled chambers such as the heart.

What happens when we bring two bubbles together? With two independently driven bubbles, the coupled flow develops within a geometry reminiscent of two chambers. We then introduce pulsatile forcing, allowing the bubble to expand and contract while flow structures interact within the confined cavity. Such interacting vortices and moving interfaces provide a simple physical platform for exploring fluid–structure interactions relevant to artificial organs and biomimetic systems.

Can we go one step further and give a bubble an anatomy? Rather than imposing a rigid mould, we use an open wireframe to gently guide the growing bubble and bias its shape. The membrane remains free to deform under the competing effects of pressure and surface tension, while the framework provides the geometric cues.

Soap films are famous for their ability to form minimal surfaces—the shapes that emerge naturally from surface tension. Here, we combine that geometric tendency with controlled flow forcing:

Flow forcing + minimal surfaces = anatomic bubbles.

The result is a playful physical model in which geometry shapes the flow, and the flow brings the anatomy to life.