Abstract: Numerical wimulations have been performed in time-developing plane mixing layers of the viscoelastic second-order fluids with pseudo-spectral method. Roll-up,Pairing and merging of large eddies were examined at high Reynolds numbers and low Deborah numbers. The effect of viscoelastics on the evolution of the large coherent structure was shown by making a comparison between the second-order and Newtonian fluids at the same Reynolds numbers.

Key words: mixing layer, viscoelastic second-order fluids, numerical simulation, pseudo-spectral method, coherent structure