Data from: Asymmetric fluid flow in helical pipes inspired by shark intestines

Unlike human intestines, which are long, hollow tubes, the intestines of
sharks and rays contain interior helical structures surrounding a
cylindrical hole. One function of these structures may be to create
asymmetric flow, favoring passage of fluid down the digestive tract, from
anterior to posterior. Here, we design and 3D print biomimetic models of
shark intestines, in both rigid and deformable materials. We use the rigid
models to test which physical parameters of the interior helices (the
pitch, the hole radius, the tilt angle, and the number of turns) yield the
largest flow asymmetries. These asymmetries exceed those of traditional
Tesla valves, structures specifically designed to create flow asymmetry
without any moving parts. When we print the biomimetic models in
elastomeric materials so that flow can couple to the structure’s shape,
flow asymmetry is significantly amplified; it is 7-fold larger in
deformable structures than in rigid structures. Last, we 3D-print
deformable versions of the intestine of a dogfish shark, based on a
tomogram of a biological sample. This biomimic produces flow asymmetry
comparable to traditional Tesla valves. The ability to influence the
direction of a flow through a structure has applications in biological
tissues and artificial devices across many scales, from large industrial
pipelines to small microfluidic devices.