Interfacial pumping inspired by snails

The apple snail Pomacea canaliculata exhibits a unique feeding mechanism to collect food particles floating at the water-air interface: while underwater, it positions part of its flexible foot parallel to the water surface and generates rhythmic undulations. These undulations trigger a flow near the free surface that brings the food particles towards the mouth. With a robotic system that periodically deforms a surface, we mimic the traveling deformations observed on the snail foot. When placed underneath the air-water interface, the undulator gives rise to a net flux of liquid in the direction of the propagating deformations. As a result, particles floating at a distance are sucked into the robotic snail. By combining experiment and analytical modeling, I will discuss how this mechanism creates a pumping effect both in the viscous as well as the inertial regime that leads to large-scale transport of floating particles.