Flow-Induced Responses of Kirigami-Patterned Sheets Placed in Fluid Flow*

We present experimental observations of flow-induced structural responses and various wake topologies generated by systematically adjusting the cut geometries of kirigami patterned sheets when placed in a fluid flow. It has been shown previously that the various categories of kirigami patterns cause a variety of static and dynamic responses in flexible sheets, from smooth and steady large-scale elongations, to buckling and flutter. This in turn creates significantly varied patterns in the downstream flow. These behaviors are not just functions of the incoming flow velocity and category of kirigami pattern, but also of the specific dimensions of the cuts in each category. This study examines the changes in the critical values associated with the onset of various structural responses as the cut geometry is varied.