Geometry-induced rectification of looped oscillatory flows

In this study, we leverage geometry-induced asymmetries to rectify oscillatory flows and induce net directional transport of fluid in a looped network. We demonstrate this valveless rectification phenomenon in an experimental apparatus that consists of an acrylic flow chamber with a deformable wall connected to a syringe pump via a T-junction. Here, oscillatory flows were forced by the syringe pump. We found that the asymmetries that existed in the geometric configuration of the looped channel could be exploited to generate net directional flow and that this geometric configuration is key in determining the directionality. By varying the pumping parameters in the system, we determined a relationship between the frequency and stroke length of the forcing syringe pump and the resulting directional flow in the loop. Using an analytical model and flow computations, we posit how asymmetric flow separation occurring at the T-junction could explain the observed flows.