Meeting Abstract
Dynamically scaled mechanical models are a valuable tool to address bio-fluid-dynamic questions. Here we describe a mechanical model of a suction feeder based on the traps of the carnivorous plant Utricularia, commonly known as bladderwort. Bladderwort traps are among the smallest, fastest, and most specialized suction feeders, thus an ideal model system. This combination of small size and extreme speed makes it difficult to study the mechanics of their suction events. Here we present the design of a mechanical suction-feeder that can simulate the entry flows generated by bladderwort traps. We use scaling laws to preserve flow patterns, and experimental and computational data to simply the design. One such simplification is that opening the trap door is effectively instantaneous. Therefore, we can eliminate the door, approximate the mouth as a fixed-diameter aperture, and employ sudden-onset volume-change or pressure histories. Furthermore, the design of the cylinder and piston can be simplified, knowing that the external flow is effectively inviscid. The mechanical model is scaled up in size by a factor of 200 and in time is slowed down by a factor of 1000. The model comprises a constant-diameter cylinder and piston, actuated by a linear motor, submerged in mineral oil. The set-up is optimized for particle image velocimetry to quantify flow and pressure fields. The resulting parameter space maps will allow us to explore the lower size limit of suction feeding.
