FLOW OF NON-NEWTONIAN FLUIDS IN CORRUGATED CHANNELS

The centerline velocities and the velocity profiles were measured for fluids in a corrugated channel with the top and bottom plates sinusoid al with and without Polymer additives, using laser Doppler velocimetry . It was observed that for the range of Reynolds number studied the ve locity profiles and centerline velocities are qualitatively similar fo r the fluids with and without polymer additives. It was also observed that an increase in the aspect ratio (a/lambda; a = amplitude, lambda = wavelength) of the plates showed the presence of secondary flow in t he channel for the fluids with and without polymers in them. However, the previous study (cf. Yalamanchili et al. [1]) clearly showed that t he aspect ratio is not the appropriate non-dimensional number to be us ed in correlating normal stress data for non-Newtonian fluids. As expe cted, the velocity increased in the converging regions of the channel and decreased in the diverging regions of the channel, irrespective of the Reynolds number of the fluid flowing, the maximum and minimum vel ocity always occurred at the same location.