Investigation of the patterned surface modification on 3D vortex flow generation in a micropipe

The effects of patterned surface modification on 3D vortex flow generation in a micro capillary tube under a very low Reynolds number have been investigated. Microfabrication technology was successfully employed to pattern surface charges on the inner surfaces of a round capillary tube, which form non-uniform zeta potentials. This technique extends the heterogeneous surfaces from a flat surface to a curved surface. 3D vortices are visualized and measured at the vicinity of tube walls when an electric field is applied across the surfaces utilizing micro resolution PIV. It demonstrated that 3D vortices can also be generated by the patterned surface charges with the same polarity patches. Experimental results have been compared with numerical simulations using CFD-ACE+.