Kirigami sheets in disturbed flow

It has been shown in the past that kirigami sheets placed in uniform fluid flow can produce predictable wakes and potentially be used as flow control devices. In practical applications, however, it is expected that there will often be non-uniform incoming flow interacting with the kirigami sheets. The question then arises of how the response of the kirigami sheet and therefore its wake changes when it is placed in non-uniform incoming flow. In this work, we investigate the response of kirigami sheets with different cut patterns in disturbed flow by placing the kirigami sheets in the wake of a cylinder whose rotation can be imposed externally such that the vortices that are shed in its wake can be controlled in their shedding frequency and strength. We investigate the influence of non-uniform incoming flow on the response of kirigami sheets by quantifying the sheet's displacement synchronized with the PIV wake visualizations for different types of kirigami patterns (ribbon cuts, fractal cuts, and closed cuts) exposed to a variety of unsteady incoming flow, such as vortices at different frequencies and strength, and uniform flow approaching the sheet at an angle.