Dynamics and Wakes of Kirigami Sheets in Flow

We present the behavior and wake patterns of various kirigami patterned flexible sheets placed perpendicular to the flow, such that the fluid is forced through the pattern. These sheets can display static and dynamic flow-induced instabilities that can result in buckling or limit cycle oscillations, or undergo significant elongation while remaining stable, depending on their pattern and the flow velocity. These sheets exhibit a variety of wake patterns as a result of the varied structural responses, including vortex shedding at multiple scales and the formation of jets that redirect the incoming flow. The mean drag force triggers the three-dimensional shape of the kirigami pattern without any need for other external actuations. While similar kirigami patterns display similar structural behavior and create similar wakes, the specifics of the response can be manipulated by adjusting the geometric parameters within each category of patterns, and therefore the wake produced can be tuned as desired. This creates a potential for novel applications in flow control.



Acknowledgement: This work is partially supported by the National Science Foundation, grant number CBET 2320300.