Hydroelastic instabilities in viscoelastic flow past a cylinder confined in a channel

Experimental investigation of viscoelastic flow past a cylinder is conducte d for a polyisobutylene-based polymer solution. High-image-density particle image velocimetry is utilized to quantitatively determine the spatial feat ures of elastic wake instabilities. The viscoelastic flow bifurcates from s teady two-dimensional flow to steady three-dimensional flow for values of t he Deborah number (dimensionless flow rate) greater than a critical value. These hydroelastic flow transitions are manifested in the form of three-dim ensional cells spaced periodically along the axis of the cylinder. The elas tic flow structures do not exist in the Newtonian counterpart of creeping f low past a cylinder.