Measuring elasticity-induced unstable flow structures in a curved microchannel using confocal micro particle image velocimetry

This paper presents a measurement of the three-dimensional structures of a micellar solution flow in a curvilinear microchannel using confocal micro particle image velocimetry. An aqueous solution of cetyltrimethylammonium chloride/sodium salicylate was used as the working fluid, and fluorescent beads were added as tracer particles. With the aid of a fast-moving piezo stage, the three-dimensional flow structure was measured by scanning the flow layer by layer in the depth direction. It was found that the internal flow oscillates, and is typically twisted. In addition, the flow direction changes according to geometric curvature. Based on the statistics of velocity features, the viscoelastic flow field inside the curved microchannel shares the main features of elastic turbulence.