The Effect of Dilute Solutions of Drag Reducing Polymers on Radiated Flow Noise

The influence of a drag reducing polymer additive in water on radiated flow noise was experimentally determined. The test facility was a rotating cylinder mounted in the center of a large cylindrical tank which served as an echoic chamber for the sound power measurements. Sound power radiated from the boundary layer of the rotating cylinder was measured for concentrations of 0, 10, 100, and 1000 ppmw of Polyox WSR 301 dissolved in the water. Sound power reductions greater than 20 decibels were noted in a frequency range of 20 to 100 kHz for a concentration of 1000 ppmw. Little influence could be found in a frequency range of 1 to 20 kHz. The effect of polymer additive on the drag coefficient of a rotating cylinder is also shown.